RE: [PATCH] lib/spinlock_debug: Tweak the loop time to fit different _delay()

[Liu, Chuansheng]

Hello Peter,

> -----Original Message-----
> From: Peter Zijlstra [mailto:peterz@xxxxxxxxxxxxx]
> Sent: Wednesday, April 30, 2014 4:55 PM
> To: Wang, Xiaoming
> Cc: mingo@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Liu, Chuansheng
> Subject: Re: [PATCH] lib/spinlock_debug: Tweak the loop time to fit different
> _delay()
> 
> On Wed, Apr 30, 2014 at 06:40:38PM -0400, Wang, Xiaoming wrote:
> > loops_per_jiffy*Hz  is not always 1 second exactly
> > it depends on the realization of _delay() .
> > delay_tsc is used as _delay() in arch/x86/lib/delay.c
> 
> This just states delay() is broken. The primary response should be to
> try and fix that, no?


delay(1s_count) is accurate, but delay(1) is not accurate indeed, since executing
some instruction, then the 1 cycle delay maybe be used already.

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