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Groups > linux.debian.kernel > #62428
| From | Mike Hommey <mh@glandium.org> |
|---|---|
| Newsgroups | linux.debian.bugs.dist, linux.debian.kernel |
| Subject | Bug#911815: /usr/bin/perf_4.18: Please build perf against libbfd |
| Date | 2018-10-25 12:20 +0200 |
| Message-ID | <wMKU9-6a4-1@gated-at.bofh.it> (permalink) |
| References | <wMHjz-3U2-3@gated-at.bofh.it> <wMHjz-3U2-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Cross-posted to 2 groups.
On Thu, Oct 25, 2018 at 03:20:11PM +0900, Mike Hommey wrote: > Package: linux-perf-4.18 > Version: 4.18.10-2 > Severity: wishlist > File: /usr/bin/perf_4.18 > > Dear Maintainer, > > Running e.g. perf report with dwarf call graph info can take a long time > depending on the size of the profile and the size of dwarf info in the > binaries being profiled. That's because each address in each library is > handled by forking and executing a new addr2line process. Each addr2line > process has to parse the dwarf info of the library it's given just to > find the location of one address. Multiply by the number of addresses, > and this can quickly become ridiculous. > > Perf, however, has an alternative implementation that just uses libbfd, > so it would be much faster than spawning a large amount of new > processes, each with a large overhead. I found https://salsa.debian.org/kernel-team/linux/blob/master/debian/rules.d/tools/perf/Makefile#L27-31 This sucks badly :( I have some massive perf data that take *hours* to deal with without libbfd. With a reduced perf data, this is the kind of difference this makes: $ time perf script > /dev/null # addr2line real 3m8.718s user 1m12.606s sys 1m56.649s $ time perf script > /dev/null # libbfd real 0m4.141s user 0m3.425s sys 0m0.894s Mike
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Bug#911815: /usr/bin/perf_4.18: Please build perf against libbfd Mike Hommey <mh+reportbug@glandium.org> - 2018-10-25 08:30 +0200
Bug#911815: /usr/bin/perf_4.18: Please build perf against libbfd Mike Hommey <mh@glandium.org> - 2018-10-25 12:20 +0200
Bug#911815: /usr/bin/perf_4.18: Please build perf against libbfd Ben Hutchings <ben@decadent.org.uk> - 2018-10-26 02:20 +0200
Bug#911815: /usr/bin/perf_4.18: Please build perf against libbfd "Steinar H. Gunderson" <sesse@debian.org> - 2020-08-18 01:20 +0200
Processed: Re: Bug#911815: /usr/bin/perf_4.18: Please build perf against libbfd "Debian Bug Tracking System" <owner@bugs.debian.org> - 2018-10-26 02:20 +0200
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