Messages in this thread Patch in this message | | | From | Namhyung Kim <> | Subject | Re: [PATCH V2] perf: Speed up thread map generation | Date | Mon, 17 Mar 2014 10:45:49 +0900 |
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Hi Don,
On Fri, 14 Mar 2014 10:43:44 -0400, Don Zickus wrote: > When trying to capture perf data on a system running spejbb2013, > perf hung for about 15 minutes. This is because it took that > long to gather about 10,000 thread maps and process them. > > I don't think a user wants to wait that long. > > Instead, recognize that thread maps are roughly equivalent to > pid maps and just quickly copy those instead. > > To do this, I synthesize 'fork' events, this eventually calls > thread__fork() and copies the maps over. > > The overhead goes from 15 minutes down to about a few seconds.
[SNIP] > @@ -416,6 +453,10 @@ int perf_event__synthesize_threads(struct perf_tool *tool, > if (mmap_event == NULL) > goto out_free_comm; > > + fork_event = malloc(sizeof(fork_event->fork) + machine->id_hdr_size); > + if (fork_event == NULL) > + goto out_free_mmap; > + > if (machine__is_default_guest(machine)) > return 0;
Not related to this patch, but this will causes a memory leak.. So I think below patch is needed on top (not sure it's also needed for perf_event__synthesize_thread_map() too).
From 3c4b49b4f540c7d49ee78364b02faa0bfce59c67 Mon Sep 17 00:00:00 2001 From: Namhyung Kim <namhyung@kernel.org> Date: Mon, 17 Mar 2014 10:23:06 +0900 Subject: [PATCH] perf tools: Fix a possible memory leak
Checking default guest machine should be done before allocating event structures otherwise it'll leak memory.
Cc: Don Zickus <dzickus@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org> --- tools/perf/util/event.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c index 3e580be0f6fb..eab930d28159 100644 --- a/tools/perf/util/event.c +++ b/tools/perf/util/event.c @@ -445,6 +445,9 @@ int perf_event__synthesize_threads(struct perf_tool *tool, union perf_event *comm_event, *mmap_event, *fork_event; int err = -1; + if (machine__is_default_guest(machine)) + return 0; + comm_event = malloc(sizeof(comm_event->comm) + machine->id_hdr_size); if (comm_event == NULL) goto out; @@ -457,9 +460,6 @@ int perf_event__synthesize_threads(struct perf_tool *tool, if (fork_event == NULL) goto out_free_mmap; - if (machine__is_default_guest(machine)) - return 0; - snprintf(proc_path, sizeof(proc_path), "%s/proc", machine->root_dir); proc = opendir(proc_path); -- 1.7.11.7
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