From: Peter Zijlstra <peterz@infradead.org>
To: "Yan, Zheng" <zheng.z.yan@intel.com>
Cc: linux-kernel@vger.kernel.org, eranian@google.com, andi@firstfloor.org
Subject: Re: [RFC PATCH 0/7] perf, x86: Reduce lbr_sel_map size
Date: Fri, 4 Oct 2013 12:55:35 +0200 [thread overview]
Message-ID: <20131004105535.GH3081@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1380184093-8838-1-git-send-email-zheng.z.yan@intel.com>
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.
next prev parent reply other threads:[~2013-10-04 10:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-26 8:28 [RFC PATCH 0/7] perf, x86: Reduce lbr_sel_map size Yan, Zheng
2013-09-26 8:28 ` [RFC PATCH 1/7] " Yan, Zheng
2013-09-26 8:28 ` [RFC PATCH 2/7] perf, x86: Basic Haswell LBR call stack support Yan, Zheng
2013-09-26 8:28 ` [RFC PATCH 3/7] perf, core: replace flush_branch_stack with ctxsw callback Yan, Zheng
2013-09-26 8:28 ` [RFC PATCH 4/7] perf, x86: Save/resotre LBR stack during context switch Yan, Zheng
2013-09-26 8:28 ` [RFC PATCH 5/7] perf, core: Pass perf_sample_data to perf_callchain() Yan, Zheng
2013-09-26 8:28 ` [RFC PATCH 6/7] perf, x86: Use LBR call stack to get user callchain Yan, Zheng
2013-09-26 8:28 ` [RFC PATCH 7/7] perf, x86: Discard zero length call entries in LBR call stack Yan, Zheng
2013-10-04 10:55 ` Peter Zijlstra [this message]
2013-10-04 13:35 ` [RFC PATCH 0/7] perf, x86: Reduce lbr_sel_map size Andi Kleen
2013-10-04 14:42 ` Peter Zijlstra
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