lkml.org 
[lkml]   [2013]   [Sep]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/2] tools, perf: Add a precise event qualifier v2

* Andi Kleen <andi@firstfloor.org> wrote:

> > Your feature to export 'precise' requirements on events looks useful to
> > me. We could implement it not by special casing it implicitly but by
> > saying that if ../format/precise contains something like:
> >
> > attr:240-241
> >
> > then that's a natural extension of the config:X-Y format and should be
> > interpreted to mean mean 2 bits in the perf attr field. I.e. we could go
> > beyond the config bitfield.
> >
> > Basically the whole perf_event_attr can be thought of as a 'giant
> > bitfield', in which we can specify values to export an enumerated list of
> > events from the kernel to tooling.
> >
> > (Using attr:X-Y the config and config1 variants can be expressed as well,
> > as the config fields are inside the attr structure.)
> >
> > The positions within the perf_attr are an ABI, so this would work pretty
> > well.
>
> Wouldn't we need different bits for each architecture then? 32bit/64bit,
> some archs with weird alignment rules, maybe different for BE/LE too?
>
> Ok I suppose it could be somehow auto generated in asm-offsets.c,
> although I'm not sure how to get a bitfield offset there.

That, or we could indeed start adding specific field names as well, which
would have a natural position and order.

Thanks,

Ingo


\
 
 \ /
  Last update: 2013-09-12 20:21    [W:0.123 / U:0.376 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site