Re: [PATCH] printk: use this_cpu_{read|write} api onprintk_pending
From: Christoph Lameter
Date: Fri Nov 26 2010 - 12:11:30 EST
On Fri, 26 Nov 2010, Eric Dumazet wrote:
> I guess you read the changelog too fast ;)
No I only read the code.... ;-)
> I posted this patch after noticing printk_needs_cpu() was always used
> for the current cpu.
Ok.
> We have other functions around, that always work for the current cpu.
Ok.
> We pass cpu as a parameter, mostly because smp_processor_id() was a bit
> expensive in old kernels, and is still expensive because of sanity
> tests.
I thought sanity tests do not apply for performance testing scenarios?
smp_processor_id() is usually a simple per cpu data access and very fast.
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