Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932287Ab2F1CYE (ORCPT ); Wed, 27 Jun 2012 22:24:04 -0400 Received: from LGEMRELSE1Q.lge.com ([156.147.1.111]:43462 "EHLO LGEMRELSE1Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751564Ab2F1CYB convert rfc822-to-8bit (ORCPT ); Wed, 27 Jun 2012 22:24:01 -0400 X-AuditID: 9c93016f-b7c85ae00000559e-04-4febc03e4d07 From: Namhyung Kim To: Jovi Zhang Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , linux-kernel@vger.kernel.org Subject: Re: perf support user-space hw_breakpoint? References: <87bok7x0e1.fsf@sejong.aot.lge.com> Date: Thu, 28 Jun 2012 11:20:09 +0900 In-Reply-To: (Jovi Zhang's message of "Thu, 28 Jun 2012 09:02:02 +0800") Message-ID: <87txxwxjmu.fsf@sejong.aot.lge.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.97 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5763 Lines: 138 On Thu, 28 Jun 2012 09:02:02 +0800, Jovi Zhang wrote: > On Mon, Jun 25, 2012 at 4:26 PM, Namhyung Kim wrote: >> BTW, when I perf record on a hwbp, it failed with ENOSPC. >> I guess it's because each per-task-per-cpu event tried to >> create an event so it'd get more than supported by h/w. >> The strace told me that the fifth call to perf_event_open >> failed on my 6-core machine. >> > I have same result as you in my linux box. > This should be a bug cause by commit d1cb9f(perf target: Add uses_mmap field) > > Namhyung, How about below patch? > NAK. This uses_mmap field is needed to setup per-task-per-cpu events for perf record (mostly). Without it, perf suffered from severe scalability issues. Maybe we can change it not to create per-task-per-cpu events iff for hwbp events only, but I'm not sure it's the right thing. Thanks, Namhyung > > From 4b77b99df9ca3b99be4ccf8c4256e622aae9203f Mon Sep 17 00:00:00 2001 > From: Jovi Zhang > Date: Thu, 28 Jun 2012 07:49:41 +0800 > Subject: [PATCH] perf: revert commit d1cb9f(perf target: Add uses_mmap field) > > In my x86 4 cores cpu linux machine, using hw_breakpoint output as follows: > > Before add uses_mmap field: >  [root@jovi perf]# ./perf record -g -e mem:0x080652c8 -e mem:0x1098 -- > /usr/bin/ls >/dev/null >  [ perf record: Woken up 1 times to write data ] >  [ perf record: Captured and wrote 0.015 MB perf.data (~640 samples) ] > > After add uses_mmap field: >  [root@jovi perf]# ./perf record -e mem:0x080652c8 -e mem:0x1098 -- > /usr/bin/ls >/dev/null >    Error: sys_perf_event_open() syscall returned with 28 (No space > left on device).  /bin/dmesg may provide additional information. > >    Fatal: No CONFIG_PERF_EVENTS=y kernel support configured? > > Adding uses_mmap field in target structure will cause perf-record > creat per-task-per-cpu > event for each evsel, this will break hw_breakpoint(have limit debug > registers in cpu), > in above example, we should create dummy cpumap for hw_breakpoint > event, not per-task-per-cpu, > fix it. > > Noticed-by: Namhyung Kim > Signed-off-by: Jovi Zhang > --- > tools/perf/builtin-record.c |    3 --- > tools/perf/builtin-test.c   |    1 - > tools/perf/builtin-top.c    |    3 --- > tools/perf/util/evlist.c    |    4 +--- > tools/perf/util/target.h    |    1 - > 5 files changed, 1 insertion(+), 11 deletions(-) > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index f95840d..8128213 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -754,9 +754,6 @@ static struct perf_record record = { >                .user_freq           = UINT_MAX, >                .user_interval       = ULLONG_MAX, >                .freq                = 4000, > -               .target              = { > -                       .uses_mmap   = true, > -               }, >        }, >        .write_mode = WRITE_FORCE, >        .file_new   = true, > diff --git a/tools/perf/builtin-test.c b/tools/perf/builtin-test.c > index 5a8727c..338a0cc 100644 > --- a/tools/perf/builtin-test.c > +++ b/tools/perf/builtin-test.c > @@ -647,7 +647,6 @@ static int test__PERF_RECORD(void) >        struct perf_record_opts opts = { >                .target = { >                        .uid = UINT_MAX, > -                       .uses_mmap = true, >                }, >                .no_delay   = true, >                .freq       = 10, > diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c > index 6bb0277..cc78e06 100644 > --- a/tools/perf/builtin-top.c > +++ b/tools/perf/builtin-top.c > @@ -1165,9 +1165,6 @@ int cmd_top(int argc, const char **argv, const > char *prefix __used) >                .freq                = 4000, /* 4 KHz */ >                .mmap_pages          = 128, >                .sym_pcnt_filter     = 5, > -               .target              = { > -                       .uses_mmap   = true, > -               }, >        }; >        char callchain_default_opt[] = "fractal,0.5,callee"; >        const struct option options[] = { > diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c > index 7400fb3..e791029 100644 > --- a/tools/perf/util/evlist.c > +++ b/tools/perf/util/evlist.c > @@ -622,9 +622,7 @@ int perf_evlist__create_maps(struct perf_evlist *evlist, >        if (evlist->threads == NULL) >                return -1; > > -       if (perf_target__has_task(target)) > -               evlist->cpus = cpu_map__dummy_new(); > -       else if (!perf_target__has_cpu(target) && !target->uses_mmap) > +       if (perf_target__has_task(target) || !perf_target__has_cpu(target)) >                evlist->cpus = cpu_map__dummy_new(); >        else >                evlist->cpus = cpu_map__new(target->cpu_list); > diff --git a/tools/perf/util/target.h b/tools/perf/util/target.h > index a4be857..c43f632 100644 > --- a/tools/perf/util/target.h > +++ b/tools/perf/util/target.h > @@ -11,7 +11,6 @@ struct perf_target { >        const char   *uid_str; >        uid_t        uid; >        bool         system_wide; > -       bool         uses_mmap; > }; > > enum perf_target_errno { > -- > 1.7.9.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/