Messages in this thread | | | Date | Sat, 08 Nov 2014 13:38:39 +0900 | From | Masami Hiramatsu <> | Subject | Re: [RFC] perf-cache command interface design |
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(2014/11/07 23:43), Namhyung Kim wrote: > Hi Masami, > > 2014-11-07 (금), 17:21 +0900, Masami Hiramatsu: >> Hello, >> >> Here, I've tried to describe my idea of perf-cache subcommand interface. >> It is just a design review, not implemented yet :) >> Please give me your comments/ideas! >> >> Command-line Synopsis >> ===================== >> >> Current "perf buildid-cache [options]" are directly mapped to >> "perf cache --buildid [options]". >> >> And adding --sdt for managing SDT caches as below. >> >> Add or update SDT events in <FILES> >> perf cache --sdt --add|--update <FILES> >> >> Remove all SDT events for <FILES> >> perf cache --sdt --remove <FILES> >> >> List all SDT events >> perf cache --sdt --list >> >> And --probes for managing probe-caches as below. >> >> Add new probe-cache entries for kernel, <PATH> or <MOD>. >> perf cache --probe [--exec <PATH>|--module <MOD>] --add <SPEC> >> >> Delete existing probe-cache entries for kernel, <PATH> or/and <BUILDID>. >> perf cache --probe --del [<GROUP>:]<EVENT>[@<PATH>][#<BUILDID>] >> >> Or remove all entires for given FILES >> perf cache --probe --remove <FILES> >> >> List the probe caches(including SDT) for kernel, <PATH>, or/and <BUILDID>. >> perf cache --probe --list [@<PATH>][#<BUILDID>] >> >> Query the probe definitions. >> perf cache --probe --query [<GROUP>:]<EVENT>[@<PATH>][#<BUILDID>] >> >> Note that --probes also can be used for managing SDT events, which has % prefix >> e.g. >> Add all SDT events for <PATH> >> perf cache --probe --exec <PATH> --add '%*:*' >> >> Remove some SDT events for <PATH> >> perf cache --probe --del '%some:events@<PATH>' >> >> Or remove all SDT events for <BUILDID> >> perf cache --probe --del '%*:*#<BUILDID>' > > I'd prefer sub-command to option for this mandatory (and exclusive) > behavior. What about like this?
I consider this will also confusing users because it's different from other subcommands. And Arnaldo gives us a better solution :)
> > perf cache kprobe add [-m <module>] <spec> [<spec>...] > perf cache kprobe del [<group>:]<event> [<event>...] > perf cache kprobe list [-m <module>] > > perf cache uprobe add -x <path> <spec> [<spec>...] > perf cache uprobe del [<group>:]<event> [<event>...] > perf cache uprobe list [-x <path>]
Since perf has only "probe" subcommand, we shouldn't separate uprobe and kprobe.
> > perf cache sdt [add|del|update] <file> [<file>...] > perf cache sdt list [-b <build-id>] [<file>...] > > >> >> >> File Format >> =========== >> All the cache files are placed under ~/.debug/ by default. >> The paths of buildid cache of binary/symbols are not changed. >> >> The SDT/probe caches are placed under the ~/.debug/.probes/path/to/bin/bu/ildid >> and that is linked to ~/.debug/.probes/.buildid/bu/ildid >> # To avoid conflict with files under /probes/*, I picked up .probes/. > > However, to be used with perf record, we need a way to find a matching > probe cache file from a event name (or group/provider name, preferably). > What about having something like below: > > $ cat ~/.debug/.probes/event.map > PROVIDER1 /path/to/some/where > PROVIDER2 /path/to/other/place
Hmm, agreed. We'd better have this kind of provider index file to accelerate searching.
> When perf record see a cached event used, it first searches its > provider/group name from the event.map file. And then read bulid-id > from the matching file on the path and finally find a cached event > definition from ~/.debug/.probes/.buildid/bu/ildid file. > > >> >> This SDT/probe caches contain probe-definitions as following format. >> ---- >> #buildid:BUILDID >> #path:PATH >> p:%PROVIDER/EVENT PATH:OFFSET [ARGS] > > It seems PATH is redundant and we don't need to repeat it everyline > IMHO. Since it need post-processing anyway, maybe it's better to just > make it simpler, like: > > %:PROVIDER/EVENT OFFSET [ARGS]
Hmm, this is not good because this line will not be able to pass to tracing/uprobe_events... And also, I think we can compress this cache with gzip, then such redundancy will not be a problem.
Thank you,
-- Masami HIRAMATSU Software Platform Research Dept. Linux Technology Research Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com
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