From: Andi Kleen <andi@firstfloor.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andi Kleen <andi@firstfloor.org>,
acme@kernel.org, jolsa@kernel.org, eranian@google.com,
linux-kernel@vger.kernel.org, mingo@kernel.org,
Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH 09/11] x86, perf: Support sysfs files depending on SMT status
Date: Mon, 18 Jan 2016 23:28:32 +0100 [thread overview]
Message-ID: <20160118222832.GK4698@two.firstfloor.org> (raw)
In-Reply-To: <20160118180614.GV6357@twins.programming.kicks-ass.net>
> So one obvious problem with this is that a concurrent hotplug operation
> can toggle ht_on resulting in bogus measurements.
>
> I'm not sure there's anything we can do about that, other than WARN in
> the tool if it finds inconsistent results; does it?
Right. Supporting a good interface for user programs to be informed
of CPU hotplug would be useful for a lot of things, but currently
it doesn't exist and it's definitely outside the scope of this
patchkit. If such an interface existed perf stat could use it
to reconfigure itself.
It's hard to do a good sanity check unfortunately.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2016-01-18 22:28 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-16 1:12 Add top down metrics to perf stat Andi Kleen
2016-01-16 1:12 ` [PATCH 01/11] perf, tools: Dont stop PMU parsing on alias parse error Andi Kleen
2016-01-16 1:12 ` [PATCH 02/11] perf, tools: Parse an .aggr-per-core event attribute Andi Kleen
2016-01-16 1:12 ` [PATCH 03/11] perf, tools, stat: Force --per-core mode for .aggr-per-core aliases Andi Kleen
2016-01-16 1:12 ` [PATCH 04/11] perf, tools, stat: Avoid fractional digits for integer scales Andi Kleen
2016-01-16 1:12 ` [PATCH 05/11] perf, tools, stat: Scale values by unit before metrics Andi Kleen
2016-01-16 1:12 ` [PATCH 06/11] perf, tools, stat: Basic support for TopDown in perf stat Andi Kleen
2016-01-16 1:12 ` [PATCH 07/11] perf, tools, stat: Add computation of TopDown formulas Andi Kleen
2016-01-16 1:12 ` [PATCH 08/11] perf, tools, stat: Add extra output of counter values with -v Andi Kleen
2016-01-16 1:12 ` [PATCH 09/11] x86, perf: Support sysfs files depending on SMT status Andi Kleen
2016-01-18 18:03 ` Peter Zijlstra
2016-01-18 18:06 ` Peter Zijlstra
2016-01-18 22:28 ` Andi Kleen [this message]
2016-01-16 1:12 ` [PATCH 10/11] x86, perf: Add Top Down events to Intel Core Andi Kleen
2016-01-16 1:12 ` [PATCH 11/11] x86, perf: Add Top Down events to Intel Atom Andi Kleen
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