linux-kernel - Re: [PATCH] perf callchain: Pass relative address to hist entry

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Date:   Wed, 25 Oct 2017 10:34:32 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Namhyung Kim <namhyung@...nel.org>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Jiri Olsa <jolsa@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>, kernel-team@....com,
        Milian Wolff <milian.wolff@...b.com>
Subject: Re: [PATCH] perf callchain: Pass relative address to hist entry

On Wed, Oct 25, 2017 at 11:12:09AM +0900, Namhyung Kim wrote:
> The addr_location->addr should have relative address to be passed to
> hist entry so that it can compare with others which might come from a
> different address space.
> 
> The callchain_cursor_node->ip already has a relative address thus it
> should not map it again.  But I found a bug handling cumulative
> (children) entries.  For chilren entries that has no self period, the
> al->addr (so he->ip) ends up having an doubly-mapped address.
> 
> It seems to be there from the beginning but only affects entries that
> have no srclines - finding srcline itself is done using a different
> address but it will show the invalid address if no srcline was found.
> 
> Tested-by: Milian Wolff <milian.wolff@...b.com>
> Fixes: c7405d85d7a3 ("perf tools: Update cpumode for each cumulative entry")
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>

hum, I'm getting differences in hist entries for:

 $ perf record --all-user -ga sleep 1
 $ perf perf report --stdio > ...
 ...
 $ diff -puw  /tmp/o.old /tmp/o.new


jirka


---
@@ -51,7 +51,7 @@
                           |
                            --0.94%--0x3

-     3.38%     0.00%  Web Content      libxul.so                    [.] 0xffff8087f8e046a5
+     3.38%     0.00%  Web Content      libxul.so                    [.] 0x00000000031c16a5
             |
             ---0x31c16a5
                |
@@ -91,7 +91,7 @@
                |
                 --1.62%--malloc

-     2.47%     0.00%  Compositor       libxul.so                    [.] 0xffff80e6f2807790
+     2.47%     0.00%  Compositor       libxul.so                    [.] 0x0000000000b9b790
             |
             ---0xb9b790
                |
@@ -163,7 +163,7 @@
             |
             ---0x72be62f5fdc55d00

-     1.05%     0.00%  Compositor       libxul.so                    [.] 0xffff80e6f280f100
+     1.05%     0.00%  Compositor       libxul.so                    [.] 0x0000000000ba3100
             |
             ---0xba3100
                |