Messages in this thread | | | Subject | Re: [PATCH] perf symbol: Fix kernel symbol address display | From | Thomas Richter <> | Date | Tue, 21 Apr 2020 13:18:03 +0200 |
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On 4/20/20 10:46 PM, Arnaldo Carvalho de Melo wrote: > Em Wed, Apr 15, 2020 at 09:07:44AM +0200, Thomas Richter escreveu: >> Running commands >> >> ./perf record -e rb0000 -- find . >> ./perf report -v > > Or when pressing 'V' in the TUI. > >> reveals symbol names and its addresses. There is a mismatch between > > Yeah, an address that at some point was put there to help with debugging > the symbol resolution, IIRC how it looked like when looking at > > readelf -sW vmlinux > > Or any other DSO, for instance, for a glibc symbol here: > > Using 'perf report -s pid,dso,sym' then pressing 'V': > > 1.55% 20325:perf /usr/lib64/libc-2.30.so 0x161825 B [.] __strlen_avx2 > > [acme@five perf]$ readelf -sW /usr/lib64/libc-2.30.so | grep strlen_avx2 > 24371: 0000000000161810 414 FUNC LOCAL DEFAULT 15 __strlen_avx2 > [acme@five perf]$ > > Can you check if doing in /lib/modules/.../build/vmlinux produces what > appears when 'V' is in place? >
Yes, I used latest 5.7.0rc2 and did ./perf record -e rb0000 -- find ./perf report -s pid,dso,sym and pressed 'V' in the TUI.
This gives 6.06% 9986:find /lib/modules/5.7 0x1f0c86 v [k] check_chain_key and [root@m35lp76 ~]# readelf -sW /lib/modules/5.7.0-rc2d-perf+/build/vmlinux | fgrep check_chain_key 20698: 00000000001f0c70 486 FUNC LOCAL DEFAULT 1 check_chain_key [root@m35lp76 ~]#
which is perfectly good and in the range.
> And perhaps we can also show the DSO offset and the rip as it gets laid > out in memory in the end? So we have all the informations? > > - Arnaldo >
I do not follow you here, do you mean something like DSO-name+offset for example libc-2.30.so+0x123?
Thanks
-- Thomas Richter, Dept 3252, IBM s390 Linux Development, Boeblingen, Germany -- Vorsitzender des Aufsichtsrats: Matthias Hartmann Geschäftsführung: Dirk Wittkopp Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294
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