From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org,
Corey Ashford <cjashfor@linux.vnet.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 2/2] perf_counter: optimize context switch between identical inherited contexts
Date: Fri, 22 May 2009 10:16:09 +0200 [thread overview]
Message-ID: <1242980169.26820.617.camel@twins> (raw)
In-Reply-To: <18966.10666.517218.332164@cargo.ozlabs.ibm.com>
On Fri, 2009-05-22 at 14:27 +1000, Paul Mackerras wrote:
> Since we don't have individual fds for the counters in a cloned
> context, the only thing that can make two clones of a given parent
> different after they have been cloned is enabling or disabling all
> counters with prctl. To account for this, we keep a count of the
> number of enabled counters in each context. Two contexts must have
> the same number of enabled counters to be considered equivalent.
Curious point that.. so prctl() can disable counters it doesn't own.
Shouldn't we instead fix that?
next prev parent reply other threads:[~2009-05-22 8:16 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-22 4:17 [PATCH 1/2] perf_counter: dynamically allocate tasks' perf_counter_context struct [v2] Paul Mackerras
2009-05-22 4:27 ` [PATCH 2/2] perf_counter: optimize context switch between identical inherited contexts Paul Mackerras
2009-05-22 8:16 ` Peter Zijlstra [this message]
2009-05-22 9:56 ` Paul Mackerras
2009-05-22 10:08 ` Peter Zijlstra
2009-05-23 12:38 ` Ingo Molnar
2009-05-23 13:06 ` Peter Zijlstra
2009-05-24 23:55 ` Paul Mackerras
2009-05-22 8:32 ` Peter Zijlstra
2009-05-22 8:57 ` Ingo Molnar
2009-05-22 9:02 ` Peter Zijlstra
2009-05-22 10:14 ` Ingo Molnar
2009-05-22 9:29 ` Paul Mackerras
2009-05-22 9:22 ` Peter Zijlstra
2009-05-22 9:42 ` Peter Zijlstra
2009-05-22 10:07 ` Paul Mackerras
2009-05-22 10:05 ` Paul Mackerras
2009-05-22 10:11 ` Ingo Molnar
2009-05-22 10:27 ` [tip:perfcounters/core] perf_counter: Optimize " tip-bot for Paul Mackerras
2009-05-24 11:33 ` Ingo Molnar
2009-05-25 6:18 ` Paul Mackerras
2009-05-25 6:54 ` Ingo Molnar
2009-05-22 10:36 ` [tip:perfcounters/core] perf_counter: fix !PERF_COUNTERS build failure tip-bot for Ingo Molnar
2009-05-22 13:46 ` [PATCH 2/2] perf_counter: optimize context switch between identical inherited contexts Peter Zijlstra
2009-05-25 0:15 ` Paul Mackerras
2009-05-25 10:38 ` Peter Zijlstra
2009-05-25 10:50 ` Peter Zijlstra
2009-05-25 11:06 ` Paul Mackerras
2009-05-25 11:27 ` Peter Zijlstra
2009-05-22 8:06 ` [PATCH 1/2] perf_counter: dynamically allocate tasks' perf_counter_context struct [v2] Peter Zijlstra
2009-05-22 9:30 ` Paul Mackerras
2009-05-22 10:27 ` [tip:perfcounters/core] perf_counter: Dynamically allocate tasks' perf_counter_context struct tip-bot for Paul Mackerras
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