From: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
To: Stephane Eranian <eranian@google.com>
Cc: linux-kernel@vger.kernel.org, Andi Kleen <andi@firstfloor.org>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Peter Zijlstra <peterz@infradead.org>,
Namhyung Kim <namhyung@gmail.com>, Jiri Olsa <jolsa@redhat.com>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH v2 00/16] perf: add memory access sampling support
Date: Tue, 6 Nov 2012 17:52:21 -0300 [thread overview]
Message-ID: <20121106205220.GF13629@infradead.org> (raw)
In-Reply-To: <1352123463-7346-1-git-send-email-eranian@google.com>
Em Mon, Nov 05, 2012 at 02:50:47PM +0100, Stephane Eranian escreveu:
> Or if one is interested in the data view:
> $ perf mem -t load rep --sort=symbol_daddr,cost
> # Samples: 19K of event 'cpu/mem-loads/pp'
> # Total cost : 1013994
> # Sort order : symbol_daddr,cost
> #
> # Overhead Samples Data Symbol Cost
> # ........ ........... ...................... .......
> #
> 0.10% 1 [.] 0x00007f67dffe8038 986
> 0.09% 1 [.] 0x00007f67df91a750 890
> 0.08% 1 [.] 0x00007f67e288fba8 826
>
> CAVEAT: Note that the data addresses are not resolved correctly currently due to a
> problem in perf data symbol resolution code which I have not been able to
> uncover so far.
Stephane,
Those data addresses mostly are on the stack, we need reverse
resolution using DWARF location expressions to figure out what is the
name of a variable that is on a particular address, etc.
Masami, have you played with this already? I mean:
[root@sandy acme]# perf mem -t load rep --stdio --sort=symbol,symbol_daddr,cost
# Samples: 30 of event 'cpu/mem-loads/pp'
# Total cost : 640
# Sort order : symbol,symbol_daddr,cost
#
# Overhead Samples Symbol Data Symbol Cost
# ........ ........... ...................... ...................... .......
#
55.00% 1 [k] lookup_fast [k] 0xffff8803b7521bd4 352
5.47% 1 [k] cache_alloc_refill [k] 0xffff880407705024 35
3.44% 1 [k] cache_alloc_refill [k] 0xffff88041d8527d8 22
3.28% 1 [k] run_timer_softirq [k] 0xffff88041e2c3e90 21
2.50% 1 [k] __list_add [k] 0xffff8803b7521d68 16
2.19% 1 [.] __strcoll_l [.] 0x00007fffa8d44080 14
1.88% 1 [.] __strcoll_l [.] 0x00007fffa8d44104 12
If we go to the annotation browser to see where is that lookup_fast hitting we get:
100.00 │ mov -0x34(%rbp),%eax
How to map 0xffff8803b7521bd4 to a stack variable, struct members and all?
Humm, for userspace we have PERF_SAMPLE_REGS_USER for the dwarf unwinder we
need for userspace, but what about reverse mapping of kernel variables? Jiri?
- Arnaldo
next prev parent reply other threads:[~2012-11-06 20:52 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-05 13:50 [PATCH v2 00/16] perf: add memory access sampling support Stephane Eranian
2012-11-05 13:50 ` [PATCH v2 01/16] perf/x86: improve sysfs event mapping with event string Stephane Eranian
2012-11-05 13:50 ` [PATCH v2 02/16] perf/x86: add flags to event constraints Stephane Eranian
2012-11-05 13:50 ` [PATCH v2 03/16] perf, core: Add a concept of a weightened sample Stephane Eranian
2012-11-05 20:01 ` Arnaldo Carvalho de Melo
2012-11-05 20:07 ` Arnaldo Carvalho de Melo
2012-11-05 22:51 ` Andi Kleen
2012-11-05 13:50 ` [PATCH v2 04/16] perf: add minimal support for PERF_SAMPLE_WEIGHT Stephane Eranian
2012-11-05 13:50 ` [PATCH v2 05/16] perf, tools: Add arbitary aliases and support names with - Stephane Eranian
2012-11-14 7:34 ` [tip:perf/core] perf " tip-bot for Andi Kleen
2012-11-05 13:50 ` [PATCH v2 06/16] perf: add support for PERF_SAMPLE_ADDR in dump_sampple() Stephane Eranian
2012-11-05 13:50 ` [PATCH v2 07/16] perf: add generic memory sampling interface Stephane Eranian
2012-11-05 13:50 ` [PATCH v2 08/16] perf/x86: add memory profiling via PEBS Load Latency Stephane Eranian
2012-11-06 13:31 ` Andi Kleen
2012-11-06 14:29 ` Stephane Eranian
2012-11-06 18:50 ` Andi Kleen
2012-11-06 19:37 ` Stephane Eranian
2012-11-07 14:39 ` Stephane Eranian
2012-11-05 13:50 ` [PATCH v2 09/16] perf/x86: export PEBS load latency threshold register to sysfs Stephane Eranian
2012-11-05 13:50 ` [PATCH v2 10/16] perf/x86: add support for PEBS Precise Store Stephane Eranian
2012-11-05 13:50 ` [PATCH v2 11/16] perf tools: add mem access sampling core support Stephane Eranian
2012-11-05 13:50 ` [PATCH v2 12/16] perf report: add support for mem access profiling Stephane Eranian
2012-11-05 13:51 ` [PATCH v2 13/16] perf record: " Stephane Eranian
2012-11-05 13:51 ` [PATCH v2 14/16] perf tools: add new mem command for memory " Stephane Eranian
2012-11-06 15:44 ` Arnaldo Carvalho de Melo
2012-11-06 15:49 ` Stephane Eranian
2012-11-06 16:51 ` Arnaldo Carvalho de Melo
2012-11-06 17:05 ` Arnaldo Carvalho de Melo
2012-11-06 15:50 ` Arnaldo Carvalho de Melo
2012-11-06 15:57 ` Stephane Eranian
2012-11-06 17:07 ` Arnaldo Carvalho de Melo
2012-11-05 13:51 ` [PATCH v2 15/16] perf: add PERF_RECORD_MISC_MMAP_DATA to RECORD_MMAP Stephane Eranian
2012-11-05 13:51 ` [PATCH v2 16/16] perf tools: detect data vs. text mappings Stephane Eranian
2012-11-06 20:52 ` Arnaldo Carvalho de Melo [this message]
2012-11-07 7:38 ` [PATCH v2 00/16] perf: add memory access sampling support Namhyung Kim
2012-11-07 10:02 ` Stephane Eranian
2012-11-07 14:53 ` Masami Hiramatsu
2012-11-07 14:56 ` Stephane Eranian
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