Messages in this thread | | | Date | Wed, 30 Mar 2022 15:22:37 +0200 | Subject | Re: [PATCH] perf tools: Stop depending on .git files for building PERF-VERSION-FILE | From | Matthieu Baerts <> |
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Hi John,
On 30/03/2022 12:22, John Garry wrote: > This essentially reverts commit c72e3f04b45fb2e50cdd81a50c3778c6a57251d8 > and commit 4e666cdb06eede2069a7b1a96a1359d1c441a3eb. > > In commit c72e3f04b45f ("tools/perf/build: Speed up git-version test on > re-make"), a makefile dependency on .git/HEAD was added. The background is > that running PERF-VERSION-FILE is relatively slow, and commands like > "git describe" are particularly slow. > > In commit 4e666cdb06ee ("perf tools: Fix dependency for version file > creation"), an additional dependency on .git/ORIG_HEAD was added, as > .git/HEAD may not change for "git reset --hard HEAD^" command. However, > depending on whether we're on a branch or not, a "git cherry-pick" may > not lead to the version being updated. > > As discussed with the git community in [0], using git internal files for > dependencies is not reliable. Commit 4e666cdb06ee also breaks some build > scenarios [1]. > > As mentioned, c72e3f04b45f was added to speed up the build. However in > commit 7572733b8499 ("perf tools: Fix version kernel tag") we removed the > call to "git describe", so just revert Makefile.perf back to same as pre > c72e3f04b45f and the build should not be so slow, as below: > > Pre 7572733b8499: > $> time util/PERF-VERSION-GEN > PERF_VERSION = 5.17.rc8.g4e666cdb06ee > > real 0m0.110s > user 0m0.091s > sys 0m0.019s > > Post 7572733b8499: > $> time util/PERF-VERSION-GEN > PERF_VERSION = 5.17.rc8.g7572733b8499 > > real 0m0.039s > user 0m0.036s > sys 0m0.007s > > [0] https://lore.kernel.org/git/87wngkpddp.fsf@igel.home/T/#m4a4dd6de52fdbe21179306cd57b3761eb07f45f8 > [1] https://lore.kernel.org/linux-perf-users/20220329093120.4173283-1-matthieu.baerts@tessares.net/T/#u > > Fixes: 4e666cdb06ee ("perf tools: Fix dependency for version file creation") > Reported-by: Matthieu Baerts <matthieu.baerts@tessares.net> > Signed-off-by: John Garry <john.garry@huawei.com>
Thank you for your patch, I just tested it and it also fixes the issue I reported!
Cheers, Matt -- Tessares | Belgium | Hybrid Access Solutions www.tessares.net
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