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Message-ID: <f7d246d4-edae-4b4c-8b19-ad6fa66e8ea1@gmail.com>
Date: Tue, 16 Jul 2024 19:29:48 +0800
From: royenheart <royenheart@...il.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: vmolnaro@...hat.com, peterz@...radead.org, mingo@...hat.com,
acme@...nel.org, mark.rutland@....com, alexander.shishkin@...ux.intel.com,
jolsa@...nel.org, irogers@...gle.com, adrian.hunter@...el.com,
kan.liang@...ux.intel.com, linux-perf-users@...r.kernel.org,
linux-kernel@...r.kernel.org, Yuan Tan <tanyuan@...ylab.org>
Subject: Re: [PATCH 1/1] perf archive: unpack to correct dir given by perf
On 2024/7/12 12:35, Namhyung Kim wrote:
> Hello,
>
> On Mon, Jul 08, 2024 at 02:04:31AM +0800, Haoze Xie wrote:
>> In perf-archive.sh, the code segment that defines 'PERF_BUILDID_DIR' is
>> advanced before 'unpack' operation for subsequent use, followed by a
>> 'mkdir' operation to ensure that the dir exists. Symbols in 'unpack' will
>> be extracted to correct dir given by perf.
>>
>> When '--unpack' param is appointed, the symbols are extracted to '~/.debug'
>> folder by default, without using 'PERF_BUILDID_DIR' given by perf. This
>> will cause perf to be unable to find the correct buildid's path when users
>> configured buildid.dir in 'perf config' or used '--buildid-dir' cli param,
>> since perf will read these params and put them in 'PERF_BUILDID_DIR' env.
>> 'perf script' and 'perf report' will use the env as the basis for buildid
>> indexing.
>
> Can you please add an example command line and the output for the error
> case? It'd be helpful to understand the problem more intuitively.
>
>>
>> Fixes: e43c64c971e4 ("perf archive: Add new option '--unpack' to expand tarballs")
>> Signed-off-by: Haoze Xie <royenheart@...il.com>
>> Signed-off-by: Yuan Tan <tanyuan@...ylab.org>
>> ---
>> tools/perf/perf-archive.sh | 28 +++++++++++++++-------------
>> 1 file changed, 15 insertions(+), 13 deletions(-)
>>
>> diff --git a/tools/perf/perf-archive.sh b/tools/perf/perf-archive.sh
>> index 6ed7e52ab881..f29bbc129056 100755
>> --- a/tools/perf/perf-archive.sh
>> +++ b/tools/perf/perf-archive.sh
>> @@ -23,6 +23,19 @@ while [ $# -gt 0 ] ; do
>> fi
>> done
>>
>> +#
>> +# PERF_BUILDID_DIR environment variable set by perf
>> +# path to buildid directory, default to $HOME/.debug
>> +#
>> +if [ -z $PERF_BUILDID_DIR ]; then
>> + PERF_BUILDID_DIR=~/.debug/
>> +else
>> + # append / to make substitutions work
>> + PERF_BUILDID_DIR=$PERF_BUILDID_DIR/
>> +fi
>> +
>> +mkdir -p $PERF_BUILDID_DIR
>> +
>> if [ $UNPACK -eq 1 ]; then
>> if [ ! -z "$UNPACK_TAR" ]; then # tar given as an argument
>> if [ ! -e "$UNPACK_TAR" ]; then
>> @@ -65,25 +78,14 @@ if [ $UNPACK -eq 1 ]; then
>> fi
>>
>> # unzip the perf.data file in the current working directory and debug symbols in ~/.debug directory
>> - tar xvf $TARGET && tar xvf $PERF_SYMBOLS.tar.bz2 -C ~/.debug
>> + tar xvf $TARGET && tar xvf $PERF_SYMBOLS.tar.bz2 -C $PERF_BUILDID_DIR
>>
>> else # perf tar generated by perf archive (contains only debug symbols)
>
> Off-topic. I'm surprised by the comment placement.
> It'd be nice if you (or someone else) can update the whole file and
> remove the unnecessary whitespaces altogether.
>
> Thanks,
> Namhyung
>
>
>> - tar xvf $TARGET -C ~/.debug
>> + tar xvf $TARGET -C $PERF_BUILDID_DIR
>> fi
>> exit 0
>> fi
>>
>> -#
>> -# PERF_BUILDID_DIR environment variable set by perf
>> -# path to buildid directory, default to $HOME/.debug
>> -#
>> -if [ -z $PERF_BUILDID_DIR ]; then
>> - PERF_BUILDID_DIR=~/.debug/
>> -else
>> - # append / to make substitutions work
>> - PERF_BUILDID_DIR=$PERF_BUILDID_DIR/
>> -fi
>> -
>> BUILDIDS=$(mktemp /tmp/perf-archive-buildids.XXXXXX)
>>
>> perf buildid-list -i $PERF_DATA --with-hits | grep -v "^ " > $BUILDIDS
>> --
>> 2.25.1
>>
I have two machines A and B, I use 'perf record' and 'perf archive' to get
a buildid archive 'perf.data.tar.bz2' on A:
$ perf record -a -g -- sleep 1
$ perf archive
then I transfer 'perf.data' and its buildid archive to B. On machine B, I
use 'perf archive' to extract the buildid:
$ perf archive --unpack
$ Found target file for unpacking: ./perf.data.tar.bz2
$ .build-id/d1/a727ab038085dbbb50e74c812e5a6e8502e8c7
$ ...
But when I use 'perf script' to view hotspots, no function names are shown:
$ perf script
$ No kallsyms or vmlinux with build-id
$ 251c1248b97a17df394058a189dffe381169ddcd was found
$ perf 1770 [000] 1022235.467607: 1 cycles:P:
$ ffffffff8ae9ceb6 [unknown] ([kernel.kallsyms])
$ ffffffff8ae15af5 [unknown] ([kernel.kallsyms])
$ ffffffff8ae0f83b [unknown] ([kernel.kallsyms])
$ ......
The problem is, I used 'perf config' to change buildid search path before:
$ perf config --user buildid.dir=/usr/local/symbols
$ cat ~/.perfconfig
$ # this file is auto-generated.
$ [buildid]
$ dir = /usr/local/symbols
But 'perf archive --unpack' just extract them to '~/.debug', which makes
perf can't found right path to search for buildid info. If I add
'buildid-dir' param to replace buildid path defined in perfconfig, problem
can be solved temporarily:
$ ./perf --buildid-dir ~/.debug script
$ perf 1770 [000] 1022235.467607: 1 cycles:P:
$ ffffffff8ae9ceb6 native_write_msr+0x6 ([kernel.kallsyms])
$ ffffffff8ae15af5 intel_pmu_enable_all+0x15 ([kernel.kallsyms])
$ ffffffff8ae0f83b x86_pmu_enable+0x1ab ([kernel.kallsyms])
The code that determines the buildid path is in the
'util/config.c:set_buildid_dir' function, which will generate
'PERF_BUILDID_DIR' var.
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