From: Alexander Shishkin <alexander.shishkin@linux.intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org, jolsa@redhat.com,
adrian.hunter@intel.com, mathieu.poirier@linaro.org,
mark.rutland@arm.com, alexander.shishkin@linux.intel.com
Subject: Re: [PATCH v2 4/4] perf/x86/intel/pt: Opportunistically use single range output mode
Date: Fri, 25 Oct 2019 15:19:38 +0300 [thread overview]
Message-ID: <87blu5ggpx.fsf@ashishki-desk.ger.corp.intel.com> (raw)
In-Reply-To: <20191024135632.GE4114@hirez.programming.kicks-ass.net>
Peter Zijlstra <peterz@infradead.org> writes:
> On Tue, Oct 22, 2019 at 12:58:12PM +0300, Alexander Shishkin wrote:
>> Most of PT implementations support Single Range Output mode, which is
>> an alternative to ToPA that can be used for a single contiguous buffer
>> and if we don't require an interrupt, that is, in AUX snapshot mode.
>>
>> Now that perf core will use high order allocations for the AUX buffer,
>> in many cases the first condition will also be satisfied.
>>
>> The two most obvious benefits of the Single Range Output mode over the
>> ToPA are:
>> * not having to allocate the ToPA table(s),
>> * not using the ToPA walk hardware.
>>
>> Make use of this functionality where available and appropriate.
>
> This seems independent of the snapshot stuff, right?
Yes, it depends on the previous PT driver patch for context,
though. I'll drop it from the set.
Regards,
--
Alex
prev parent reply other threads:[~2019-10-25 12:19 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-22 9:58 [PATCH v2 0/4] perf: Add AUX data sampling Alexander Shishkin
2019-10-22 9:58 ` [PATCH v2 1/4] perf: Allow using AUX data in perf samples Alexander Shishkin
2019-10-24 13:52 ` Peter Zijlstra
2019-10-24 14:01 ` Peter Zijlstra
2019-10-25 12:52 ` Alexander Shishkin
2019-10-24 14:06 ` Peter Zijlstra
2019-10-25 12:21 ` Alexander Shishkin
2019-10-24 14:09 ` Peter Zijlstra
2019-10-24 14:12 ` Peter Zijlstra
2019-10-22 9:58 ` [PATCH v2 2/4] perf/x86/intel/pt: Factor out starting the trace Alexander Shishkin
2019-10-22 9:58 ` [PATCH v2 3/4] perf/x86/intel/pt: Add sampling support Alexander Shishkin
2019-10-22 9:58 ` [PATCH v2 4/4] perf/x86/intel/pt: Opportunistically use single range output mode Alexander Shishkin
2019-10-23 15:09 ` Alexander Shishkin
2019-10-24 13:56 ` Peter Zijlstra
2019-10-25 12:19 ` Alexander Shishkin [this message]
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