Re: [RFC] perf-cache command interface design

[Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>]

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

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

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

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>]

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


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.

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