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authorKan Liang <kan.liang@intel.com>2017-09-11 05:23:14 +0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2017-09-18 15:40:19 +0300
commit91e467bc568f15da2eac688e131010601e889184 (patch)
treed6e2441af518536d534eacde9a4e549ffeb8ec42 /tools/perf/util/machine.h
parent56de5b63ffaff859f75c19aff057ee10f20c6c07 (diff)
downloadlinux-91e467bc568f15da2eac688e131010601e889184.tar.xz
perf machine: Use hashtable for machine threads
To process any events, it needs to find the thread in the machine first. The machine maintains a rb tree to store all threads. The rb tree is protected by a rw lock. It is not a problem for current perf which serially processing events. However, it will have scalability performance issue to process events in parallel, especially on a heavy load system which have many threads. Introduce a hashtable to divide the big rb tree into many samll rb tree for threads. The index is thread id % hashtable size. It can reduce the lock contention. Committer notes: Renamed some variables and function names to reduce semantic confusion: 'struct threads' pointers: thread -> threads threads hastable index: tid -> hash_bucket struct threads *machine__thread() -> machine__threads() Cast tid to (unsigned int) to handle -1 in machine__threads() (Kan Liang) Signed-off-by: Kan Liang <kan.liang@intel.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Lukasz Odzioba <lukasz.odzioba@intel.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1505096603-215017-2-git-send-email-kan.liang@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/machine.h')
-rw-r--r--tools/perf/util/machine.h23
1 files changed, 18 insertions, 5 deletions
diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
index 3cdb1340f917..fe2f05848050 100644
--- a/tools/perf/util/machine.h
+++ b/tools/perf/util/machine.h
@@ -23,6 +23,17 @@ extern const char *ref_reloc_sym_names[];
struct vdso_info;
+#define THREADS__TABLE_BITS 8
+#define THREADS__TABLE_SIZE (1 << THREADS__TABLE_BITS)
+
+struct threads {
+ struct rb_root entries;
+ pthread_rwlock_t lock;
+ unsigned int nr;
+ struct list_head dead;
+ struct thread *last_match;
+};
+
struct machine {
struct rb_node rb_node;
pid_t pid;
@@ -30,11 +41,7 @@ struct machine {
bool comm_exec;
bool kptr_restrict_warned;
char *root_dir;
- struct rb_root threads;
- pthread_rwlock_t threads_lock;
- unsigned int nr_threads;
- struct list_head dead_threads;
- struct thread *last_match;
+ struct threads threads[THREADS__TABLE_SIZE];
struct vdso_info *vdso_info;
struct perf_env *env;
struct dsos dsos;
@@ -48,6 +55,12 @@ struct machine {
};
};
+static inline struct threads *machine__threads(struct machine *machine, pid_t tid)
+{
+ /* Cast it to handle tid == -1 */
+ return &machine->threads[(unsigned int)tid % THREADS__TABLE_SIZE];
+}
+
static inline
struct map *__machine__kernel_map(struct machine *machine, enum map_type type)
{