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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-03-25 03:53:42 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-03-25 03:53:42 -0300
commit03dd4cb26d967f9588437b0fc9cc0e8353322bb7 (patch)
treefa581f6dc1c0596391690d1f67eceef3af8246dc /Documentation/trace
parentd4e493caf788ef44982e131ff9c786546904d934 (diff)
Linux-libre 4.5-gnu
Diffstat (limited to 'Documentation/trace')
-rw-r--r--Documentation/trace/events-msr.txt37
-rw-r--r--Documentation/trace/postprocess/decode_msr.py37
2 files changed, 74 insertions, 0 deletions
diff --git a/Documentation/trace/events-msr.txt b/Documentation/trace/events-msr.txt
new file mode 100644
index 000000000..78c383bf0
--- /dev/null
+++ b/Documentation/trace/events-msr.txt
@@ -0,0 +1,37 @@
+
+The x86 kernel supports tracing most MSR (Model Specific Register) accesses.
+To see the definition of the MSRs on Intel systems please see the SDM
+at http://www.intel.com/sdm (Volume 3)
+
+Available trace points:
+
+/sys/kernel/debug/tracing/events/msr/
+
+Trace MSR reads
+
+read_msr
+
+msr: MSR number
+val: Value written
+failed: 1 if the access failed, otherwise 0
+
+
+Trace MSR writes
+
+write_msr
+
+msr: MSR number
+val: Value written
+failed: 1 if the access failed, otherwise 0
+
+
+Trace RDPMC in kernel
+
+rdpmc
+
+The trace data can be post processed with the postprocess/decode_msr.py script
+
+cat /sys/kernel/debug/tracing/trace | decode_msr.py /usr/src/linux/include/asm/msr-index.h
+
+to add symbolic MSR names.
+
diff --git a/Documentation/trace/postprocess/decode_msr.py b/Documentation/trace/postprocess/decode_msr.py
new file mode 100644
index 000000000..0ab40e0db
--- /dev/null
+++ b/Documentation/trace/postprocess/decode_msr.py
@@ -0,0 +1,37 @@
+#!/usr/bin/python
+# add symbolic names to read_msr / write_msr in trace
+# decode_msr msr-index.h < trace
+import sys
+import re
+
+msrs = dict()
+
+with open(sys.argv[1] if len(sys.argv) > 1 else "msr-index.h", "r") as f:
+ for j in f:
+ m = re.match(r'#define (MSR_\w+)\s+(0x[0-9a-fA-F]+)', j)
+ if m:
+ msrs[int(m.group(2), 16)] = m.group(1)
+
+extra_ranges = (
+ ( "MSR_LASTBRANCH_%d_FROM_IP", 0x680, 0x69F ),
+ ( "MSR_LASTBRANCH_%d_TO_IP", 0x6C0, 0x6DF ),
+ ( "LBR_INFO_%d", 0xdc0, 0xddf ),
+)
+
+for j in sys.stdin:
+ m = re.search(r'(read|write)_msr:\s+([0-9a-f]+)', j)
+ if m:
+ r = None
+ num = int(m.group(2), 16)
+ if num in msrs:
+ r = msrs[num]
+ else:
+ for er in extra_ranges:
+ if er[1] <= num <= er[2]:
+ r = er[0] % (num - er[1],)
+ break
+ if r:
+ j = j.replace(" " + m.group(2), " " + r + "(" + m.group(2) + ")")
+ print j,
+
+