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SubjectRe: [RFC] perf-cache command interface design
Em Mon, Nov 10, 2014 at 07:59:24PM +0900, Masami Hiramatsu escreveu:
> Hello,
>
> Here is the second try for the probe-cache. This version simplifies
> the synopsis, and unifies the SDT and probe caches.
> Please give me your comments/ideas!
>
> Command-line Synopsis
> =====================
>
> Add elf(or symbols) and probe-caches of SDT if exists in <FILES>
> perf cache --add <FILES> [--probe <SPEC>] # for user programs

Why the --probe above? Shouldn't this be just (if you are talking about
ELF files only):

perf cache --add <FILES>

> perf cache --kcore <FILE> [--probe <SPEC>] # for kcore ?

Adrian, aren't kcore files easily identifiable as such and thus could be
added as:

perf cache --add <FILES>

> perf cache --probe <SPEC> # for the current kernel

Why do we need a --probe here? Don't they always start with a character
that is seldomly used in ELF file names and thus we could get away with
not requiring --probe?

> Remove caches related to <FILES> or <BUILDIDS>
> perf cache --remove <FILES>|<BUILDIDS>
>
> Show all probe caches(including SDT) or buildids
> perf cache --list [probe|buildid]
>
> Delete existing probe-cache entries for kernel, <PATH> or/and <BUILDID>.
> perf cache --probe-del [<GROUP>:]<EVENT>[@<PATH>][#<BUILDID>]

Ditto, i.e. can't we just use:

perf cache --remove [<GROUP>:]<EVENT>[@<PATH>][#<BUILDID>]

And it figure out that this is a probe that is being removed?

> Query the probe definitions.
> perf cache --query [<GROUP>:]<EVENT>[@<PATH>][#<BUILDID>]

Replace --query with --show?

> File Format
> ===========
> All the cache files are placed under ~/.debug/ by default.
> Elf caches are ~/.debug/path/to/file/bu/ildid/elf
> Symbols caches are ~/.debug/path/to/file/bu/ildid/syms
> Probes(and SDT) are ~/.debug/path/to/file/bu/ildid/probes
> And ~/.debug/path/to/file/bu/ildid/ is linked to ~/.debug/.buildid/bu/ildid
> Optionally, we can gzip the probes file.

Ok!

> This probe caches contain probe-definitions as following format.
> ----
> #buildid:BUILDID
> #spec:SDT
> p:sdt_<PROVIDER>/<EVENT> PATH:OFFSET [ARGS]
> ...
> #spec:* $params
> p:probe_<GROUP>/<EVENT> _text+OFFSET [ARGS]
> ...
> ----
> So the #spec: line gives the information what probe spec has been given.
> This will be used for updating.
>
> And all the "probe_" and "sdt_" prefix will be replaced by % in the command line,
> e.g.
>
> perf record -e %<PROVIDER>/<EVENT> -> this records sdt_PROVIDER/EVENT
>
> 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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