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perf machine: Use hashtable for machine threads

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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>
This commit is contained in:
Kan Liang
2017-09-10 19:23:14 -07:00
committed by Arnaldo Carvalho de Melo
parent 56de5b63ff
commit 91e467bc56
4 changed files with 119 additions and 68 deletions
Download Patch File Download Diff File Expand all files Collapse all files

23
tools/perf/builtin-trace.c
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@@ -2730,20 +2730,23 @@ DEFINE_RESORT_RB(threads, (thread__nr_events(a->thread->priv) < thread__nr_event
static size_t trace__fprintf_thread_summary(struct trace *trace, FILE *fp)
{
DECLARE_RESORT_RB_MACHINE_THREADS(threads, trace->host);
size_t printed = trace__fprintf_threads_header(fp);
struct rb_node *nd;
int i;
if (threads == NULL) {
fprintf(fp, "%s", "Error sorting output by nr_events!\n");
return 0;
for (i = 0; i < THREADS__TABLE_SIZE; i++) {
DECLARE_RESORT_RB_MACHINE_THREADS(threads, trace->host, i);
if (threads == NULL) {
fprintf(fp, "%s", "Error sorting output by nr_events!\n");
return 0;
}
resort_rb__for_each_entry(nd, threads)
printed += trace__fprintf_thread(fp, threads_entry->thread, trace);
resort_rb__delete(threads);
}
resort_rb__for_each_entry(nd, threads)
printed += trace__fprintf_thread(fp, threads_entry->thread, trace);
resort_rb__delete(threads);
return printed;
}