[lkml]   [2014]   [Nov]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC] perf-cache command interface design
Em Mon, Nov 10, 2014 at 01:05:45PM +0100, Hagen Paul Pfeifer escreveu:
> On 7 November 2014 09:21, Masami Hiramatsu
> <> wrote:
> > 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/.
> A little bit late: but why ~/.debug? Why not $XDG_CACHE_HOME/perf/ as

Why "perf"?

> the root for all perf related files? debug is not unique nor is it sufficient

Probably should be some other name then, but ~/.debug/ is there since
the build-id cache was introduced, guess this is why it is being kept so
far in Masami's proposal.

> to meet file hierarchy: man file-hierarchy(8)


It starts in $HOME/.debug/ because this is not supposed to be a system
wide cache, a developer can, for instance:

1. perf record myapp
2. edit myapp.c
3. rebuild it
4. perf record myapp
5. perf diff

And it will show the difference from the previous version, for which it
stored a copy of its binary on its private, keyed by build-id, cache.

So this is not merely a place where we will read stuff from.

If somebody decides to have it in a place accessible by multiple users
on the same system, then, yes, some more suitable place outside its
$HOME is needed, and then tooling should look there as well as on the
places it already looks for such files, i.e. $HOME/.debug/,
/usr/lib/debug (where foo-debuginfo packages store stuff, also keyed by
build-id), /lib/modules/$KVR/, etc.

- Arnaldo

 \ /
  Last update: 2014-11-10 14:01    [W:0.252 / U:3.112 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site