lkml.org 
[lkml]   [2013]   [Oct]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH 0/7] perf, x86: Reduce lbr_sel_map size
On Thu, Sep 26, 2013 at 04:28:06PM +0800, Yan, Zheng wrote:
> From: "Yan, Zheng" <zheng.z.yan@intel.com>
>
> Haswell has a new feature that utilizes the existing Last Branch Record
> facility to record call chains. When the feature is enabled, function
> call will be collected as normal, but as return instructions are executed
> the last captured branch record is popped from the on-chip LBR registers.
> The LBR call stack facility can help perf to get call chains of progam
> without frame pointer. When perf tool requests PERF_SAMPLE_CALLCHAIN +
> PERF_SAMPLE_BRANCH_USER, this feature is dynamically enabled by default.
> This feature can be disabled/enabled through an attribute file in the cpu
> pmu sysfs directory.
>
> The main change since previous patch series is:
> Patch 3 introduces PMU context switch callback, and uses the callback to
> unify the flush branch stack codeo.
>
> Patch 4 uses the context switch callback to save/restore the LBR stack.

From what I can tell this is the exact same drivel I rejected earlier.

Same shitty changelogs, same shitty code.

Do not waste my time like this.


\
 
 \ /
  Last update: 2013-10-04 13:01    [W:0.068 / U:0.144 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site