Messages in this thread | | | Date | Wed, 11 Feb 2015 11:57:42 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [perf/core PATCH v2 3/4] perf buildid-cache: Add new buildid cache if update target is not cached |
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Em Wed, Feb 11, 2015 at 11:49:28AM -0300, Arnaldo Carvalho de Melo escreveu: > Em Tue, Feb 10, 2015 at 06:18:56PM +0900, Masami Hiramatsu escreveu: > > Add new buildid cache if the update target file is not cached. > > This can happen when an old binary is replaced by new one > > after caching the old one. In this case, user sees his operation > > just failed. But it does not look straight, since user just > > pass the binary "path", not "build-id". > > > > ---- > > # ./perf buildid-cache --add ./perf > > (update ./perf to new binary) > > # ./perf buildid-cache --update ./perf > > ./perf wasn't in the cache > > Humm, without re-reading the original motivation for the '--update' > operation I would think it was about finding all build-ids in the cache > that are for a binary with that path, remove them and insert this new > one, no? > > Checking...
commit eeb49845425375481f14c0e5721f88242642e88e Author: Namhyung Kim <namhyung.kim@lge.com> Date: Thu Feb 7 18:02:11 2013 +0900
perf buildid-cache: Add --update option
When adding vmlinux file to build-id cache, it'd be fail since kallsyms dso with a same build-id was already added by perf record.
So one needs to remove the kallsyms first to add vmlinux into the cache. Add --update option for doing it at once.
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So this was really a 'remove the file that is pointed by this build-id' and replace with this new file, i.e. there is both a vmlinux _and_ a kallsyms file for the same build-id. When wanting to use one or the other and existing a link in the cache, one uses this --update thing.
That is ok for cases where there are multiple symtabs in the cache for a given build-id, but as you mention above, it is confusing for updating by _pathname_.
What a 'update' by pathname would mean? I guess it would be to remove 'old', i.e. 'not up-to-date' stuff, i.e. older build-ids that that pathname had in the past, and leave just this new stuff.
The way you did it make '--update path' be equivalent to '--add path'.
- Arnaldo
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