From: Dave Jones <davej@redhat.com>
To: akpm@linux-foundation.org
Cc: lenb@kernel.org, linux-acpi@vger.kernel.org,
linux-kernel@vger.kernel.org, efault@gmx.de, len.brown@intel.com,
mingo@elte.hu, rusty@rustcorp.com.au, tglx@linutronix.de,
venkatesh.pallipadi@intel.com, yakui.zhao@intel.com,
yanmin_zhang@linux.intel.com
Subject: Re: [patch for 2.6.30 2/2] arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c: avoid cross-CPU interrupts
Date: Sat, 11 Apr 2009 20:06:05 -0400 [thread overview]
Message-ID: <20090412000605.GA23869@redhat.com> (raw)
In-Reply-To: <200904110617.n3B6HJ7W026502@imap1.linux-foundation.org>
On Fri, Apr 10, 2009 at 11:17:18PM -0700, Andrew Morton wrote:
> From: Andrew Morton <akpm@linux-foundation.org>
>
> In drv_read(), check to see whether we can run the rdmsr() on the current
> CPU. If so, do that. So smp_call_function_single() can avoid the IPI.
Wouldn't it be a better to make smp_call_function_single do this check
itself, so all callers benefit from this optimisation?
*looks*
Wait, won't this already be caught by this code in smp_call_function_single() ?
286 this_cpu = get_cpu();
...
291 if (cpu == this_cpu) {
292 local_irq_save(flags);
293 func(info);
294 local_irq_restore(flags);
295 } else {
Dave
next prev parent reply other threads:[~2009-04-12 0:08 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-11 6:17 [patch for 2.6.30 2/2] arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c: avoid cross-CPU interrupts akpm
2009-04-11 6:37 ` Jaswinder Singh Rajput
2009-04-12 0:06 ` Dave Jones [this message]
2009-04-12 0:46 ` Andrew Morton
2009-04-14 8:51 ` Rusty Russell
2009-04-14 17:18 ` Andrew Morton
2009-04-15 6:35 ` Rusty Russell
2009-04-20 3:22 ` Len Brown
2009-04-20 2:57 ` Len Brown
2009-04-20 3:20 ` Andrew Morton
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