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authorLennart Poettering <lennart@poettering.net>2013-11-26 18:58:44 +0100
committerLennart Poettering <lennart@poettering.net>2013-11-26 18:58:44 +0100
commitbf807d4dbf27c783db8dfd7f4eca321ae4be5b00 (patch)
treebc8810a5a2b08cfb1c4ab3d9ea48646c280a3010
parentb8e891e699e1336c5527f8203e4e8f67c9bbeb84 (diff)
journald: keep statistics on how of we hit/miss the mmap cache
-rw-r--r--src/journal/mmap-cache.c25
-rw-r--r--src/journal/mmap-cache.h3
-rw-r--r--src/journal/sd-journal.c4
3 files changed, 29 insertions, 3 deletions
diff --git a/src/journal/mmap-cache.c b/src/journal/mmap-cache.c
index 6c9194a1a5..117dc2f3a5 100644
--- a/src/journal/mmap-cache.c
+++ b/src/journal/mmap-cache.c
@@ -72,6 +72,9 @@ struct MMapCache {
int n_ref;
unsigned n_windows;
+ unsigned n_hit, n_missed;
+
+
Hashmap *fds;
Hashmap *contexts;
@@ -542,13 +545,19 @@ int mmap_cache_get(
/* Check whether the current context is the right one already */
r = try_context(m, fd, prot, context, keep_always, offset, size, ret);
- if (r != 0)
+ if (r != 0) {
+ m->n_hit ++;
return r;
+ }
/* Search for a matching mmap */
r = find_mmap(m, fd, prot, context, keep_always, offset, size, ret);
- if (r != 0)
+ if (r != 0) {
+ m->n_hit ++;
return r;
+ }
+
+ m->n_missed++;
/* Create a new mmap */
return add_mmap(m, fd, prot, context, keep_always, offset, size, st, ret);
@@ -578,3 +587,15 @@ void mmap_cache_close_context(MMapCache *m, unsigned context) {
context_free(c);
}
+
+unsigned mmap_cache_get_hit(MMapCache *m) {
+ assert(m);
+
+ return m->n_hit;
+}
+
+unsigned mmap_cache_get_missed(MMapCache *m) {
+ assert(m);
+
+ return m->n_missed;
+}
diff --git a/src/journal/mmap-cache.h b/src/journal/mmap-cache.h
index 0c42fb88e6..912336d7c2 100644
--- a/src/journal/mmap-cache.h
+++ b/src/journal/mmap-cache.h
@@ -34,3 +34,6 @@ MMapCache* mmap_cache_unref(MMapCache *m);
int mmap_cache_get(MMapCache *m, int fd, int prot, unsigned context, bool keep_always, uint64_t offset, size_t size, struct stat *st, void **ret);
void mmap_cache_close_fd(MMapCache *m, int fd);
void mmap_cache_close_context(MMapCache *m, unsigned context);
+
+unsigned mmap_cache_get_hit(MMapCache *m);
+unsigned mmap_cache_get_missed(MMapCache *m);
diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c
index 4579e9ee2d..1c91f007b7 100644
--- a/src/journal/sd-journal.c
+++ b/src/journal/sd-journal.c
@@ -1831,8 +1831,10 @@ _public_ void sd_journal_close(sd_journal *j) {
if (j->inotify_fd >= 0)
close_nointr_nofail(j->inotify_fd);
- if (j->mmap)
+ if (j->mmap) {
+ log_debug("mmap cache statistics: %u hit, %u miss", mmap_cache_get_hit(j->mmap), mmap_cache_get_missed(j->mmap));
mmap_cache_unref(j->mmap);
+ }
free(j->path);
free(j->unique_field);