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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-12-15 14:52:16 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-12-15 14:52:16 -0300
commit8d91c1e411f55d7ea91b1183a2e9f8088fb4d5be (patch)
treee9891aa6c295060d065adffd610c4f49ecf884f3 /tools/perf/Documentation
parenta71852147516bc1cb5b0b3cbd13639bfd4022dc8 (diff)
Linux-libre 4.3.2-gnu
Diffstat (limited to 'tools/perf/Documentation')
-rw-r--r--tools/perf/Documentation/intel-bts.txt86
-rw-r--r--tools/perf/Documentation/intel-pt.txt751
-rw-r--r--tools/perf/Documentation/itrace.txt22
-rw-r--r--tools/perf/Documentation/perf-bench.txt4
-rw-r--r--tools/perf/Documentation/perf-inject.txt23
-rw-r--r--tools/perf/Documentation/perf-record.txt36
-rw-r--r--tools/perf/Documentation/perf-report.txt39
-rw-r--r--tools/perf/Documentation/perf-script.txt39
-rw-r--r--tools/perf/Documentation/perf-top.txt21
9 files changed, 952 insertions, 69 deletions
diff --git a/tools/perf/Documentation/intel-bts.txt b/tools/perf/Documentation/intel-bts.txt
new file mode 100644
index 000000000..8bdc93bd7
--- /dev/null
+++ b/tools/perf/Documentation/intel-bts.txt
@@ -0,0 +1,86 @@
+Intel Branch Trace Store
+========================
+
+Overview
+========
+
+Intel BTS could be regarded as a predecessor to Intel PT and has some
+similarities because it can also identify every branch a program takes. A
+notable difference is that Intel BTS has no timing information and as a
+consequence the present implementation is limited to per-thread recording.
+
+While decoding Intel BTS does not require walking the object code, the object
+code is still needed to pair up calls and returns correctly, consequently much
+of the Intel PT documentation applies also to Intel BTS. Refer to the Intel PT
+documentation and consider that the PMU 'intel_bts' can usually be used in
+place of 'intel_pt' in the examples provided, with the proviso that per-thread
+recording must also be stipulated i.e. the --per-thread option for
+'perf record'.
+
+
+perf record
+===========
+
+new event
+---------
+
+The Intel BTS kernel driver creates a new PMU for Intel BTS. The perf record
+option is:
+
+ -e intel_bts//
+
+Currently Intel BTS is limited to per-thread tracing so the --per-thread option
+is also needed.
+
+
+snapshot option
+---------------
+
+The snapshot option is the same as Intel PT (refer Intel PT documentation).
+
+
+auxtrace mmap size option
+-----------------------
+
+The mmap size option is the same as Intel PT (refer Intel PT documentation).
+
+
+perf script
+===========
+
+By default, perf script will decode trace data found in the perf.data file.
+This can be further controlled by option --itrace. The --itrace option is
+the same as Intel PT (refer Intel PT documentation) except that neither
+"instructions" events nor "transactions" events (and consequently call
+chains) are supported.
+
+To disable trace decoding entirely, use the option --no-itrace.
+
+
+dump option
+-----------
+
+perf script has an option (-D) to "dump" the events i.e. display the binary
+data.
+
+When -D is used, Intel BTS packets are displayed.
+
+To disable the display of Intel BTS packets, combine the -D option with
+--no-itrace.
+
+
+perf report
+===========
+
+By default, perf report will decode trace data found in the perf.data file.
+This can be further controlled by new option --itrace exactly the same as
+perf script.
+
+
+perf inject
+===========
+
+perf inject also accepts the --itrace option in which case tracing data is
+removed and replaced with the synthesized events. e.g.
+
+ perf inject --itrace -i perf.data -o perf.data.new
diff --git a/tools/perf/Documentation/intel-pt.txt b/tools/perf/Documentation/intel-pt.txt
new file mode 100644
index 000000000..c94c9de31
--- /dev/null
+++ b/tools/perf/Documentation/intel-pt.txt
@@ -0,0 +1,751 @@
+Intel Processor Trace
+=====================
+
+Overview
+========
+
+Intel Processor Trace (Intel PT) is an extension of Intel Architecture that
+collects information about software execution such as control flow, execution
+modes and timings and formats it into highly compressed binary packets.
+Technical details are documented in the Intel 64 and IA-32 Architectures
+Software Developer Manuals, Chapter 36 Intel Processor Trace.
+
+Intel PT is first supported in Intel Core M and 5th generation Intel Core
+processors that are based on the Intel micro-architecture code name Broadwell.
+
+Trace data is collected by 'perf record' and stored within the perf.data file.
+See below for options to 'perf record'.
+
+Trace data must be 'decoded' which involves walking the object code and matching
+the trace data packets. For example a TNT packet only tells whether a
+conditional branch was taken or not taken, so to make use of that packet the
+decoder must know precisely which instruction was being executed.
+
+Decoding is done on-the-fly. The decoder outputs samples in the same format as
+samples output by perf hardware events, for example as though the "instructions"
+or "branches" events had been recorded. Presently 3 tools support this:
+'perf script', 'perf report' and 'perf inject'. See below for more information
+on using those tools.
+
+The main distinguishing feature of Intel PT is that the decoder can determine
+the exact flow of software execution. Intel PT can be used to understand why
+and how did software get to a certain point, or behave a certain way. The
+software does not have to be recompiled, so Intel PT works with debug or release
+builds, however the executed images are needed - which makes use in JIT-compiled
+environments, or with self-modified code, a challenge. Also symbols need to be
+provided to make sense of addresses.
+
+A limitation of Intel PT is that it produces huge amounts of trace data
+(hundreds of megabytes per second per core) which takes a long time to decode,
+for example two or three orders of magnitude longer than it took to collect.
+Another limitation is the performance impact of tracing, something that will
+vary depending on the use-case and architecture.
+
+
+Quickstart
+==========
+
+It is important to start small. That is because it is easy to capture vastly
+more data than can possibly be processed.
+
+The simplest thing to do with Intel PT is userspace profiling of small programs.
+Data is captured with 'perf record' e.g. to trace 'ls' userspace-only:
+
+ perf record -e intel_pt//u ls
+
+And profiled with 'perf report' e.g.
+
+ perf report
+
+To also trace kernel space presents a problem, namely kernel self-modifying
+code. A fairly good kernel image is available in /proc/kcore but to get an
+accurate image a copy of /proc/kcore needs to be made under the same conditions
+as the data capture. A script perf-with-kcore can do that, but beware that the
+script makes use of 'sudo' to copy /proc/kcore. If you have perf installed
+locally from the source tree you can do:
+
+ ~/libexec/perf-core/perf-with-kcore record pt_ls -e intel_pt// -- ls
+
+which will create a directory named 'pt_ls' and put the perf.data file and
+copies of /proc/kcore, /proc/kallsyms and /proc/modules into it. Then to use
+'perf report' becomes:
+
+ ~/libexec/perf-core/perf-with-kcore report pt_ls
+
+Because samples are synthesized after-the-fact, the sampling period can be
+selected for reporting. e.g. sample every microsecond
+
+ ~/libexec/perf-core/perf-with-kcore report pt_ls --itrace=i1usge
+
+See the sections below for more information about the --itrace option.
+
+Beware the smaller the period, the more samples that are produced, and the
+longer it takes to process them.
+
+Also note that the coarseness of Intel PT timing information will start to
+distort the statistical value of the sampling as the sampling period becomes
+smaller.
+
+To represent software control flow, "branches" samples are produced. By default
+a branch sample is synthesized for every single branch. To get an idea what
+data is available you can use the 'perf script' tool with no parameters, which
+will list all the samples.
+
+ perf record -e intel_pt//u ls
+ perf script
+
+An interesting field that is not printed by default is 'flags' which can be
+displayed as follows:
+
+ perf script -Fcomm,tid,pid,time,cpu,event,trace,ip,sym,dso,addr,symoff,flags
+
+The flags are "bcrosyiABEx" which stand for branch, call, return, conditional,
+system, asynchronous, interrupt, transaction abort, trace begin, trace end, and
+in transaction, respectively.
+
+While it is possible to create scripts to analyze the data, an alternative
+approach is available to export the data to a postgresql database. Refer to
+script export-to-postgresql.py for more details, and to script
+call-graph-from-postgresql.py for an example of using the database.
+
+As mentioned above, it is easy to capture too much data. One way to limit the
+data captured is to use 'snapshot' mode which is explained further below.
+Refer to 'new snapshot option' and 'Intel PT modes of operation' further below.
+
+Another problem that will be experienced is decoder errors. They can be caused
+by inability to access the executed image, self-modified or JIT-ed code, or the
+inability to match side-band information (such as context switches and mmaps)
+which results in the decoder not knowing what code was executed.
+
+There is also the problem of perf not being able to copy the data fast enough,
+resulting in data lost because the buffer was full. See 'Buffer handling' below
+for more details.
+
+
+perf record
+===========
+
+new event
+---------
+
+The Intel PT kernel driver creates a new PMU for Intel PT. PMU events are
+selected by providing the PMU name followed by the "config" separated by slashes.
+An enhancement has been made to allow default "config" e.g. the option
+
+ -e intel_pt//
+
+will use a default config value. Currently that is the same as
+
+ -e intel_pt/tsc,noretcomp=0/
+
+which is the same as
+
+ -e intel_pt/tsc=1,noretcomp=0/
+
+Note there are now new config terms - see section 'config terms' further below.
+
+The config terms are listed in /sys/devices/intel_pt/format. They are bit
+fields within the config member of the struct perf_event_attr which is
+passed to the kernel by the perf_event_open system call. They correspond to bit
+fields in the IA32_RTIT_CTL MSR. Here is a list of them and their definitions:
+
+ $ grep -H . /sys/bus/event_source/devices/intel_pt/format/*
+ /sys/bus/event_source/devices/intel_pt/format/cyc:config:1
+ /sys/bus/event_source/devices/intel_pt/format/cyc_thresh:config:19-22
+ /sys/bus/event_source/devices/intel_pt/format/mtc:config:9
+ /sys/bus/event_source/devices/intel_pt/format/mtc_period:config:14-17
+ /sys/bus/event_source/devices/intel_pt/format/noretcomp:config:11
+ /sys/bus/event_source/devices/intel_pt/format/psb_period:config:24-27
+ /sys/bus/event_source/devices/intel_pt/format/tsc:config:10
+
+Note that the default config must be overridden for each term i.e.
+
+ -e intel_pt/noretcomp=0/
+
+is the same as:
+
+ -e intel_pt/tsc=1,noretcomp=0/
+
+So, to disable TSC packets use:
+
+ -e intel_pt/tsc=0/
+
+It is also possible to specify the config value explicitly:
+
+ -e intel_pt/config=0x400/
+
+Note that, as with all events, the event is suffixed with event modifiers:
+
+ u userspace
+ k kernel
+ h hypervisor
+ G guest
+ H host
+ p precise ip
+
+'h', 'G' and 'H' are for virtualization which is not supported by Intel PT.
+'p' is also not relevant to Intel PT. So only options 'u' and 'k' are
+meaningful for Intel PT.
+
+perf_event_attr is displayed if the -vv option is used e.g.
+
+ ------------------------------------------------------------
+ perf_event_attr:
+ type 6
+ size 112
+ config 0x400
+ { sample_period, sample_freq } 1
+ sample_type IP|TID|TIME|CPU|IDENTIFIER
+ read_format ID
+ disabled 1
+ inherit 1
+ exclude_kernel 1
+ exclude_hv 1
+ enable_on_exec 1
+ sample_id_all 1
+ ------------------------------------------------------------
+ sys_perf_event_open: pid 31104 cpu 0 group_fd -1 flags 0x8
+ sys_perf_event_open: pid 31104 cpu 1 group_fd -1 flags 0x8
+ sys_perf_event_open: pid 31104 cpu 2 group_fd -1 flags 0x8
+ sys_perf_event_open: pid 31104 cpu 3 group_fd -1 flags 0x8
+ ------------------------------------------------------------
+
+
+config terms
+------------
+
+The June 2015 version of Intel 64 and IA-32 Architectures Software Developer
+Manuals, Chapter 36 Intel Processor Trace, defined new Intel PT features.
+Some of the features are reflect in new config terms. All the config terms are
+described below.
+
+tsc Always supported. Produces TSC timestamp packets to provide
+ timing information. In some cases it is possible to decode
+ without timing information, for example a per-thread context
+ that does not overlap executable memory maps.
+
+ The default config selects tsc (i.e. tsc=1).
+
+noretcomp Always supported. Disables "return compression" so a TIP packet
+ is produced when a function returns. Causes more packets to be
+ produced but might make decoding more reliable.
+
+ The default config does not select noretcomp (i.e. noretcomp=0).
+
+psb_period Allows the frequency of PSB packets to be specified.
+
+ The PSB packet is a synchronization packet that provides a
+ starting point for decoding or recovery from errors.
+
+ Support for psb_period is indicated by:
+
+ /sys/bus/event_source/devices/intel_pt/caps/psb_cyc
+
+ which contains "1" if the feature is supported and "0"
+ otherwise.
+
+ Valid values are given by:
+
+ /sys/bus/event_source/devices/intel_pt/caps/psb_periods
+
+ which contains a hexadecimal value, the bits of which represent
+ valid values e.g. bit 2 set means value 2 is valid.
+
+ The psb_period value is converted to the approximate number of
+ trace bytes between PSB packets as:
+
+ 2 ^ (value + 11)
+
+ e.g. value 3 means 16KiB bytes between PSBs
+
+ If an invalid value is entered, the error message
+ will give a list of valid values e.g.
+
+ $ perf record -e intel_pt/psb_period=15/u uname
+ Invalid psb_period for intel_pt. Valid values are: 0-5
+
+ If MTC packets are selected, the default config selects a value
+ of 3 (i.e. psb_period=3) or the nearest lower value that is
+ supported (0 is always supported). Otherwise the default is 0.
+
+ If decoding is expected to be reliable and the buffer is large
+ then a large PSB period can be used.
+
+ Because a TSC packet is produced with PSB, the PSB period can
+ also affect the granularity to timing information in the absence
+ of MTC or CYC.
+
+mtc Produces MTC timing packets.
+
+ MTC packets provide finer grain timestamp information than TSC
+ packets. MTC packets record time using the hardware crystal
+ clock (CTC) which is related to TSC packets using a TMA packet.
+
+ Support for this feature is indicated by:
+
+ /sys/bus/event_source/devices/intel_pt/caps/mtc
+
+ which contains "1" if the feature is supported and
+ "0" otherwise.
+
+ The frequency of MTC packets can also be specified - see
+ mtc_period below.
+
+mtc_period Specifies how frequently MTC packets are produced - see mtc
+ above for how to determine if MTC packets are supported.
+
+ Valid values are given by:
+
+ /sys/bus/event_source/devices/intel_pt/caps/mtc_periods
+
+ which contains a hexadecimal value, the bits of which represent
+ valid values e.g. bit 2 set means value 2 is valid.
+
+ The mtc_period value is converted to the MTC frequency as:
+
+ CTC-frequency / (2 ^ value)
+
+ e.g. value 3 means one eighth of CTC-frequency
+
+ Where CTC is the hardware crystal clock, the frequency of which
+ can be related to TSC via values provided in cpuid leaf 0x15.
+
+ If an invalid value is entered, the error message
+ will give a list of valid values e.g.
+
+ $ perf record -e intel_pt/mtc_period=15/u uname
+ Invalid mtc_period for intel_pt. Valid values are: 0,3,6,9
+
+ The default value is 3 or the nearest lower value
+ that is supported (0 is always supported).
+
+cyc Produces CYC timing packets.
+
+ CYC packets provide even finer grain timestamp information than
+ MTC and TSC packets. A CYC packet contains the number of CPU
+ cycles since the last CYC packet. Unlike MTC and TSC packets,
+ CYC packets are only sent when another packet is also sent.
+
+ Support for this feature is indicated by:
+
+ /sys/bus/event_source/devices/intel_pt/caps/psb_cyc
+
+ which contains "1" if the feature is supported and
+ "0" otherwise.
+
+ The number of CYC packets produced can be reduced by specifying
+ a threshold - see cyc_thresh below.
+
+cyc_thresh Specifies how frequently CYC packets are produced - see cyc
+ above for how to determine if CYC packets are supported.
+
+ Valid cyc_thresh values are given by:
+
+ /sys/bus/event_source/devices/intel_pt/caps/cycle_thresholds
+
+ which contains a hexadecimal value, the bits of which represent
+ valid values e.g. bit 2 set means value 2 is valid.
+
+ The cyc_thresh value represents the minimum number of CPU cycles
+ that must have passed before a CYC packet can be sent. The
+ number of CPU cycles is:
+
+ 2 ^ (value - 1)
+
+ e.g. value 4 means 8 CPU cycles must pass before a CYC packet
+ can be sent. Note a CYC packet is still only sent when another
+ packet is sent, not at, e.g. every 8 CPU cycles.
+
+ If an invalid value is entered, the error message
+ will give a list of valid values e.g.
+
+ $ perf record -e intel_pt/cyc,cyc_thresh=15/u uname
+ Invalid cyc_thresh for intel_pt. Valid values are: 0-12
+
+ CYC packets are not requested by default.
+
+
+new snapshot option
+-------------------
+
+The difference between full trace and snapshot from the kernel's perspective is
+that in full trace we don't overwrite trace data that the user hasn't collected
+yet (and indicated that by advancing aux_tail), whereas in snapshot mode we let
+the trace run and overwrite older data in the buffer so that whenever something
+interesting happens, we can stop it and grab a snapshot of what was going on
+around that interesting moment.
+
+To select snapshot mode a new option has been added:
+
+ -S
+
+Optionally it can be followed by the snapshot size e.g.
+
+ -S0x100000
+
+The default snapshot size is the auxtrace mmap size. If neither auxtrace mmap size
+nor snapshot size is specified, then the default is 4MiB for privileged users
+(or if /proc/sys/kernel/perf_event_paranoid < 0), 128KiB for unprivileged users.
+If an unprivileged user does not specify mmap pages, the mmap pages will be
+reduced as described in the 'new auxtrace mmap size option' section below.
+
+The snapshot size is displayed if the option -vv is used e.g.
+
+ Intel PT snapshot size: %zu
+
+
+new auxtrace mmap size option
+---------------------------
+
+Intel PT buffer size is specified by an addition to the -m option e.g.
+
+ -m,16
+
+selects a buffer size of 16 pages i.e. 64KiB.
+
+Note that the existing functionality of -m is unchanged. The auxtrace mmap size
+is specified by the optional addition of a comma and the value.
+
+The default auxtrace mmap size for Intel PT is 4MiB/page_size for privileged users
+(or if /proc/sys/kernel/perf_event_paranoid < 0), 128KiB for unprivileged users.
+If an unprivileged user does not specify mmap pages, the mmap pages will be
+reduced from the default 512KiB/page_size to 256KiB/page_size, otherwise the
+user is likely to get an error as they exceed their mlock limit (Max locked
+memory as shown in /proc/self/limits). Note that perf does not count the first
+512KiB (actually /proc/sys/kernel/perf_event_mlock_kb minus 1 page) per cpu
+against the mlock limit so an unprivileged user is allowed 512KiB per cpu plus
+their mlock limit (which defaults to 64KiB but is not multiplied by the number
+of cpus).
+
+In full-trace mode, powers of two are allowed for buffer size, with a minimum
+size of 2 pages. In snapshot mode, it is the same but the minimum size is
+1 page.
+
+The mmap size and auxtrace mmap size are displayed if the -vv option is used e.g.
+
+ mmap length 528384
+ auxtrace mmap length 4198400
+
+
+Intel PT modes of operation
+---------------------------
+
+Intel PT can be used in 2 modes:
+ full-trace mode
+ snapshot mode
+
+Full-trace mode traces continuously e.g.
+
+ perf record -e intel_pt//u uname
+
+Snapshot mode captures the available data when a signal is sent e.g.
+
+ perf record -v -e intel_pt//u -S ./loopy 1000000000 &
+ [1] 11435
+ kill -USR2 11435
+ Recording AUX area tracing snapshot
+
+Note that the signal sent is SIGUSR2.
+Note that "Recording AUX area tracing snapshot" is displayed because the -v
+option is used.
+
+The 2 modes cannot be used together.
+
+
+Buffer handling
+---------------
+
+There may be buffer limitations (i.e. single ToPa entry) which means that actual
+buffer sizes are limited to powers of 2 up to 4MiB (MAX_ORDER). In order to
+provide other sizes, and in particular an arbitrarily large size, multiple
+buffers are logically concatenated. However an interrupt must be used to switch
+between buffers. That has two potential problems:
+ a) the interrupt may not be handled in time so that the current buffer
+ becomes full and some trace data is lost.
+ b) the interrupts may slow the system and affect the performance
+ results.
+
+If trace data is lost, the driver sets 'truncated' in the PERF_RECORD_AUX event
+which the tools report as an error.
+
+In full-trace mode, the driver waits for data to be copied out before allowing
+the (logical) buffer to wrap-around. If data is not copied out quickly enough,
+again 'truncated' is set in the PERF_RECORD_AUX event. If the driver has to
+wait, the intel_pt event gets disabled. Because it is difficult to know when
+that happens, perf tools always re-enable the intel_pt event after copying out
+data.
+
+
+Intel PT and build ids
+----------------------
+
+By default "perf record" post-processes the event stream to find all build ids
+for executables for all addresses sampled. Deliberately, Intel PT is not
+decoded for that purpose (it would take too long). Instead the build ids for
+all executables encountered (due to mmap, comm or task events) are included
+in the perf.data file.
+
+To see buildids included in the perf.data file use the command:
+
+ perf buildid-list
+
+If the perf.data file contains Intel PT data, that is the same as:
+
+ perf buildid-list --with-hits
+
+
+Snapshot mode and event disabling
+---------------------------------
+
+In order to make a snapshot, the intel_pt event is disabled using an IOCTL,
+namely PERF_EVENT_IOC_DISABLE. However doing that can also disable the
+collection of side-band information. In order to prevent that, a dummy
+software event has been introduced that permits tracking events (like mmaps) to
+continue to be recorded while intel_pt is disabled. That is important to ensure
+there is complete side-band information to allow the decoding of subsequent
+snapshots.
+
+A test has been created for that. To find the test:
+
+ perf test list
+ ...
+ 23: Test using a dummy software event to keep tracking
+
+To run the test:
+
+ perf test 23
+ 23: Test using a dummy software event to keep tracking : Ok
+
+
+perf record modes (nothing new here)
+------------------------------------
+
+perf record essentially operates in one of three modes:
+ per thread
+ per cpu
+ workload only
+
+"per thread" mode is selected by -t or by --per-thread (with -p or -u or just a
+workload).
+"per cpu" is selected by -C or -a.
+"workload only" mode is selected by not using the other options but providing a
+command to run (i.e. the workload).
+
+In per-thread mode an exact list of threads is traced. There is no inheritance.
+Each thread has its own event buffer.
+
+In per-cpu mode all processes (or processes from the selected cgroup i.e. -G
+option, or processes selected with -p or -u) are traced. Each cpu has its own
+buffer. Inheritance is allowed.
+
+In workload-only mode, the workload is traced but with per-cpu buffers.
+Inheritance is allowed. Note that you can now trace a workload in per-thread
+mode by using the --per-thread option.
+
+
+Privileged vs non-privileged users
+----------------------------------
+
+Unless /proc/sys/kernel/perf_event_paranoid is set to -1, unprivileged users
+have memory limits imposed upon them. That affects what buffer sizes they can
+have as outlined above.
+
+Unless /proc/sys/kernel/perf_event_paranoid is set to -1, unprivileged users are
+not permitted to use tracepoints which means there is insufficient side-band
+information to decode Intel PT in per-cpu mode, and potentially workload-only
+mode too if the workload creates new processes.
+
+Note also, that to use tracepoints, read-access to debugfs is required. So if
+debugfs is not mounted or the user does not have read-access, it will again not
+be possible to decode Intel PT in per-cpu mode.
+
+
+sched_switch tracepoint
+-----------------------
+
+The sched_switch tracepoint is used to provide side-band data for Intel PT
+decoding. sched_switch events are automatically added. e.g. the second event
+shown below
+
+ $ perf record -vv -e intel_pt//u uname
+ ------------------------------------------------------------
+ perf_event_attr:
+ type 6
+ size 112
+ config 0x400
+ { sample_period, sample_freq } 1
+ sample_type IP|TID|TIME|CPU|IDENTIFIER
+ read_format ID
+ disabled 1
+ inherit 1
+ exclude_kernel 1
+ exclude_hv 1
+ enable_on_exec 1
+ sample_id_all 1
+ ------------------------------------------------------------
+ sys_perf_event_open: pid 31104 cpu 0 group_fd -1 flags 0x8
+ sys_perf_event_open: pid 31104 cpu 1 group_fd -1 flags 0x8
+ sys_perf_event_open: pid 31104 cpu 2 group_fd -1 flags 0x8
+ sys_perf_event_open: pid 31104 cpu 3 group_fd -1 flags 0x8
+ ------------------------------------------------------------
+ perf_event_attr:
+ type 2
+ size 112
+ config 0x108
+ { sample_period, sample_freq } 1
+ sample_type IP|TID|TIME|CPU|PERIOD|RAW|IDENTIFIER
+ read_format ID
+ inherit 1
+ sample_id_all 1
+ exclude_guest 1
+ ------------------------------------------------------------
+ sys_perf_event_open: pid -1 cpu 0 group_fd -1 flags 0x8
+ sys_perf_event_open: pid -1 cpu 1 group_fd -1 flags 0x8
+ sys_perf_event_open: pid -1 cpu 2 group_fd -1 flags 0x8
+ sys_perf_event_open: pid -1 cpu 3 group_fd -1 flags 0x8
+ ------------------------------------------------------------
+ perf_event_attr:
+ type 1
+ size 112
+ config 0x9
+ { sample_period, sample_freq } 1
+ sample_type IP|TID|TIME|IDENTIFIER
+ read_format ID
+ disabled 1
+ inherit 1
+ exclude_kernel 1
+ exclude_hv 1
+ mmap 1
+ comm 1
+ enable_on_exec 1
+ task 1
+ sample_id_all 1
+ mmap2 1
+ comm_exec 1
+ ------------------------------------------------------------
+ sys_perf_event_open: pid 31104 cpu 0 group_fd -1 flags 0x8
+ sys_perf_event_open: pid 31104 cpu 1 group_fd -1 flags 0x8
+ sys_perf_event_open: pid 31104 cpu 2 group_fd -1 flags 0x8
+ sys_perf_event_open: pid 31104 cpu 3 group_fd -1 flags 0x8
+ mmap size 528384B
+ AUX area mmap length 4194304
+ perf event ring buffer mmapped per cpu
+ Synthesizing auxtrace information
+ Linux
+ [ perf record: Woken up 1 times to write data ]
+ [ perf record: Captured and wrote 0.042 MB perf.data ]
+
+Note, the sched_switch event is only added if the user is permitted to use it
+and only in per-cpu mode.
+
+Note also, the sched_switch event is only added if TSC packets are requested.
+That is because, in the absence of timing information, the sched_switch events
+cannot be matched against the Intel PT trace.
+
+
+perf script
+===========
+
+By default, perf script will decode trace data found in the perf.data file.
+This can be further controlled by new option --itrace.
+
+
+New --itrace option
+-------------------
+
+Having no option is the same as
+
+ --itrace
+
+which, in turn, is the same as
+
+ --itrace=ibxe
+
+The letters are:
+
+ i synthesize "instructions" events
+ b synthesize "branches" events
+ x synthesize "transactions" events
+ c synthesize branches events (calls only)
+ r synthesize branches events (returns only)
+ e synthesize tracing error events
+ d create a debug log
+ g synthesize a call chain (use with i or x)
+
+"Instructions" events look like they were recorded by "perf record -e
+instructions".
+
+"Branches" events look like they were recorded by "perf record -e branches". "c"
+and "r" can be combined to get calls and returns.
+
+"Transactions" events correspond to the start or end of transactions. The
+'flags' field can be used in perf script to determine whether the event is a
+tranasaction start, commit or abort.
+
+Error events are new. They show where the decoder lost the trace. Error events
+are quite important. Users must know if what they are seeing is a complete
+picture or not.
+
+The "d" option will cause the creation of a file "intel_pt.log" containing all
+decoded packets and instructions. Note that this option slows down the decoder
+and that the resulting file may be very large.
+
+In addition, the period of the "instructions" event can be specified. e.g.
+
+ --itrace=i10us
+
+sets the period to 10us i.e. one instruction sample is synthesized for each 10
+microseconds of trace. Alternatives to "us" are "ms" (milliseconds),
+"ns" (nanoseconds), "t" (TSC ticks) or "i" (instructions).
+
+"ms", "us" and "ns" are converted to TSC ticks.
+
+The timing information included with Intel PT does not give the time of every
+instruction. Consequently, for the purpose of sampling, the decoder estimates
+the time since the last timing packet based on 1 tick per instruction. The time
+on the sample is *not* adjusted and reflects the last known value of TSC.
+
+For Intel PT, the default period is 100us.
+
+Also the call chain size (default 16, max. 1024) for instructions or
+transactions events can be specified. e.g.
+
+ --itrace=ig32
+ --itrace=xg32
+
+To disable trace decoding entirely, use the option --no-itrace.
+
+
+dump option
+-----------
+
+perf script has an option (-D) to "dump" the events i.e. display the binary
+data.
+
+When -D is used, Intel PT packets are displayed. The packet decoder does not
+pay attention to PSB packets, but just decodes the bytes - so the packets seen
+by the actual decoder may not be identical in places where the data is corrupt.
+One example of that would be when the buffer-switching interrupt has been too
+slow, and the buffer has been filled completely. In that case, the last packet
+in the buffer might be truncated and immediately followed by a PSB as the trace
+continues in the next buffer.
+
+To disable the display of Intel PT packets, combine the -D option with
+--no-itrace.
+
+
+perf report
+===========
+
+By default, perf report will decode trace data found in the perf.data file.
+This can be further controlled by new option --itrace exactly the same as
+perf script, with the exception that the default is --itrace=igxe.
+
+
+perf inject
+===========
+
+perf inject also accepts the --itrace option in which case tracing data is
+removed and replaced with the synthesized events. e.g.
+
+ perf inject --itrace -i perf.data -o perf.data.new
diff --git a/tools/perf/Documentation/itrace.txt b/tools/perf/Documentation/itrace.txt
new file mode 100644
index 000000000..2ff946677
--- /dev/null
+++ b/tools/perf/Documentation/itrace.txt
@@ -0,0 +1,22 @@
+ i synthesize instructions events
+ b synthesize branches events
+ c synthesize branches events (calls only)
+ r synthesize branches events (returns only)
+ x synthesize transactions events
+ e synthesize error events
+ d create a debug log
+ g synthesize a call chain (use with i or x)
+
+ The default is all events i.e. the same as --itrace=ibxe
+
+ In addition, the period (default 100000) for instructions events
+ can be specified in units of:
+
+ i instructions
+ t ticks
+ ms milliseconds
+ us microseconds
+ ns nanoseconds (default)
+
+ Also the call chain size (default 16, max. 1024) for instructions or
+ transactions events can be specified.
diff --git a/tools/perf/Documentation/perf-bench.txt b/tools/perf/Documentation/perf-bench.txt
index bf3d0644b..ab632d9fb 100644
--- a/tools/perf/Documentation/perf-bench.txt
+++ b/tools/perf/Documentation/perf-bench.txt
@@ -216,6 +216,10 @@ Suite for evaluating parallel wake calls.
*requeue*::
Suite for evaluating requeue calls.
+*lock-pi*::
+Suite for evaluating futex lock_pi calls.
+
+
SEE ALSO
--------
linkperf:perf[1]
diff --git a/tools/perf/Documentation/perf-inject.txt b/tools/perf/Documentation/perf-inject.txt
index b876ae312..0c721c3e3 100644
--- a/tools/perf/Documentation/perf-inject.txt
+++ b/tools/perf/Documentation/perf-inject.txt
@@ -48,28 +48,7 @@ OPTIONS
Decode Instruction Tracing data, replacing it with synthesized events.
Options are:
- i synthesize instructions events
- b synthesize branches events
- c synthesize branches events (calls only)
- r synthesize branches events (returns only)
- x synthesize transactions events
- e synthesize error events
- d create a debug log
- g synthesize a call chain (use with i or x)
-
- The default is all events i.e. the same as --itrace=ibxe
-
- In addition, the period (default 100000) for instructions events
- can be specified in units of:
-
- i instructions
- t ticks
- ms milliseconds
- us microseconds
- ns nanoseconds (default)
-
- Also the call chain size (default 16, max. 1024) for instructions or
- transactions events can be specified.
+include::itrace.txt[]
SEE ALSO
--------
diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
index 9b9d9d086..2e9ce77b5 100644
--- a/tools/perf/Documentation/perf-record.txt
+++ b/tools/perf/Documentation/perf-record.txt
@@ -45,6 +45,21 @@ OPTIONS
param1 and param2 are defined as formats for the PMU in:
/sys/bus/event_sources/devices/<pmu>/format/*
+ There are also some params which are not defined in .../<pmu>/format/*.
+ These params can be used to overload default config values per event.
+ Here is a list of the params.
+ - 'period': Set event sampling period
+ - 'freq': Set event sampling frequency
+ - 'time': Disable/enable time stamping. Acceptable values are 1 for
+ enabling time stamping. 0 for disabling time stamping.
+ The default is 1.
+ - 'call-graph': Disable/enable callgraph. Acceptable str are "fp" for
+ FP mode, "dwarf" for DWARF mode, "lbr" for LBR mode and
+ "no" for disable callgraph.
+ - 'stack-size': user stack size for dwarf mode
+ Note: If user explicitly sets options which conflict with the params,
+ the value set by the params will be overridden.
+
- a hardware breakpoint event in the form of '\mem:addr[/len][:access]'
where addr is the address in memory you want to break in.
Access is the memory access type (read, write, execute) it can
@@ -61,7 +76,16 @@ OPTIONS
"perf report" to view group events together.
--filter=<filter>::
- Event filter.
+ Event filter. This option should follow a event selector (-e) which
+ selects tracepoint event(s). Multiple '--filter' options are combined
+ using '&&'.
+
+--exclude-perf::
+ Don't record events issued by perf itself. This option should follow
+ a event selector (-e) which selects tracepoint event(s). It adds a
+ filter expression 'common_pid != $PERFPID' to filters. If other
+ '--filter' exists, the new filter expression will be combined with
+ them by '&&'.
-a::
--all-cpus::
@@ -252,7 +276,11 @@ filter out the startup phase of the program, which is often very different.
--intr-regs::
Capture machine state (registers) at interrupt, i.e., on counter overflows for
each sample. List of captured registers depends on the architecture. This option
-is off by default.
+is off by default. It is possible to select the registers to sample using their
+symbolic names, e.g. on x86, ax, si. To list the available registers use
+--intr-regs=\?. To name registers, pass a comma separated list such as
+--intr-regs=ax,bx. The list of register is architecture dependent.
+
--running-time::
Record running and enabled time for read events (:S)
@@ -276,6 +304,10 @@ When processing pre-existing threads /proc/XXX/mmap, it may take a long time,
because the file may be huge. A time out is needed in such cases.
This option sets the time out limit. The default value is 500 ms.
+--switch-events::
+Record context switch events i.e. events of type PERF_RECORD_SWITCH or
+PERF_RECORD_SWITCH_CPU_WIDE.
+
SEE ALSO
--------
linkperf:perf-stat[1], linkperf:perf-list[1]
diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
index c33b69f33..9c7981bfd 100644
--- a/tools/perf/Documentation/perf-report.txt
+++ b/tools/perf/Documentation/perf-report.txt
@@ -81,6 +81,8 @@ OPTIONS
- cpu: cpu number the task ran at the time of sample
- srcline: filename and line number executed at the time of sample. The
DWARF debugging info must be provided.
+ - srcfile: file name of the source file of the same. Requires dwarf
+ information.
- weight: Event specific weight, e.g. memory latency or transaction
abort cost. This is the global weight.
- local_weight: Local weight version of the weight above.
@@ -109,6 +111,7 @@ OPTIONS
- mispredict: "N" for predicted branch, "Y" for mispredicted branch
- in_tx: branch in TSX transaction
- abort: TSX transaction abort.
+ - cycles: Cycles in basic block
And default sort keys are changed to comm, dso_from, symbol_from, dso_to
and symbol_to, see '--branch-stack'.
@@ -328,31 +331,23 @@ OPTIONS
--itrace::
Options for decoding instruction tracing data. The options are:
- i synthesize instructions events
- b synthesize branches events
- c synthesize branches events (calls only)
- r synthesize branches events (returns only)
- x synthesize transactions events
- e synthesize error events
- d create a debug log
- g synthesize a call chain (use with i or x)
-
- The default is all events i.e. the same as --itrace=ibxe
-
- In addition, the period (default 100000) for instructions events
- can be specified in units of:
-
- i instructions
- t ticks
- ms milliseconds
- us microseconds
- ns nanoseconds (default)
-
- Also the call chain size (default 16, max. 1024) for instructions or
- transactions events can be specified.
+include::itrace.txt[]
To disable decoding entirely, use --no-itrace.
+--full-source-path::
+ Show the full path for source files for srcline output.
+
+--show-ref-call-graph::
+ When multiple events are sampled, it may not be needed to collect
+ callgraphs for all of them. The sample sites are usually nearby,
+ and it's enough to collect the callgraphs on a reference event.
+ So user can use "call-graph=no" event modifier to disable callgraph
+ for other events to reduce the overhead.
+ However, perf report cannot show callgraphs for the event which
+ disable the callgraph.
+ This option extends the perf report to show reference callgraphs,
+ which collected by reference event, in no callgraph event.
include::callchain-overhead-calculation.txt[]
diff --git a/tools/perf/Documentation/perf-script.txt b/tools/perf/Documentation/perf-script.txt
index c82df572f..dc3ec783b 100644
--- a/tools/perf/Documentation/perf-script.txt
+++ b/tools/perf/Documentation/perf-script.txt
@@ -116,7 +116,7 @@ OPTIONS
--fields::
Comma separated list of fields to print. Options are:
comm, tid, pid, time, cpu, event, trace, ip, sym, dso, addr, symoff,
- srcline, period, flags.
+ srcline, period, iregs, flags.
Field list can be prepended with the type, trace, sw or hw,
to indicate to which event type the field list applies.
e.g., -f sw:comm,tid,time,ip,sym and -f trace:time,cpu,trace
@@ -222,6 +222,17 @@ OPTIONS
--show-mmap-events
Display mmap related events (e.g. MMAP, MMAP2).
+--show-switch-events
+ Display context switch events i.e. events of type PERF_RECORD_SWITCH or
+ PERF_RECORD_SWITCH_CPU_WIDE.
+
+--demangle::
+ Demangle symbol names to human readable form. It's enabled by default,
+ disable with --no-demangle.
+
+--demangle-kernel::
+ Demangle kernel symbol names to human readable form (for C++ kernels).
+
--header
Show perf.data header.
@@ -231,31 +242,13 @@ OPTIONS
--itrace::
Options for decoding instruction tracing data. The options are:
- i synthesize instructions events
- b synthesize branches events
- c synthesize branches events (calls only)
- r synthesize branches events (returns only)
- x synthesize transactions events
- e synthesize error events
- d create a debug log
- g synthesize a call chain (use with i or x)
-
- The default is all events i.e. the same as --itrace=ibxe
-
- In addition, the period (default 100000) for instructions events
- can be specified in units of:
-
- i instructions
- t ticks
- ms milliseconds
- us microseconds
- ns nanoseconds (default)
-
- Also the call chain size (default 16, max. 1024) for instructions or
- transactions events can be specified.
+include::itrace.txt[]
To disable decoding entirely, use --no-itrace.
+--full-source-path::
+ Show the full path for source files for srcline output.
+
SEE ALSO
--------
linkperf:perf-record[1], linkperf:perf-script-perl[1],
diff --git a/tools/perf/Documentation/perf-top.txt b/tools/perf/Documentation/perf-top.txt
index 776aec4d0..f6a23eb29 100644
--- a/tools/perf/Documentation/perf-top.txt
+++ b/tools/perf/Documentation/perf-top.txt
@@ -208,6 +208,27 @@ Default is to monitor all CPUS.
This option sets the time out limit. The default value is 500 ms.
+-b::
+--branch-any::
+ Enable taken branch stack sampling. Any type of taken branch may be sampled.
+ This is a shortcut for --branch-filter any. See --branch-filter for more infos.
+
+-j::
+--branch-filter::
+ Enable taken branch stack sampling. Each sample captures a series of consecutive
+ taken branches. The number of branches captured with each sample depends on the
+ underlying hardware, the type of branches of interest, and the executed code.
+ It is possible to select the types of branches captured by enabling filters.
+ For a full list of modifiers please see the perf record manpage.
+
+ The option requires at least one branch type among any, any_call, any_ret, ind_call, cond.
+ The privilege levels may be omitted, in which case, the privilege levels of the associated
+ event are applied to the branch filter. Both kernel (k) and hypervisor (hv) privilege
+ levels are subject to permissions. When sampling on multiple events, branch stack sampling
+ is enabled for all the sampling events. The sampled branch type is the same for all events.
+ The various filters must be specified as a comma separated list: --branch-filter any_ret,u,k
+ Note that this feature may not be available on all processors.
+
INTERACTIVE PROMPTING KEYS
--------------------------