Re: [Xen-devel] [PATCHv3 0/4] Use ticket locks for spinlocks

[David Vrabel <david.vrabel@xxxxxxxxxx>]

On 21/04/15 11:22, Jan Beulich wrote:
>>>> On 21.04.15 at 12:11, <david.vrabel@xxxxxxxxxx> wrote:
>> We have analysed the affect of this series on interrupt latency (by
>> measuring the duration of irq disable/enable regions) and there is no
>> signficant impact.
>>
>> http://xenbits.xen.org/people/dvrabel/bar2_comp.png 
> 
> Thanks for doing this!
> 
>> Interestingly, the biggest offenders for long critical sections are
>> bare irq disable/enable regions, and some of these are really bad (10s
>> of ms)!
>>
>> http://xenbits.xen.org/people/dvrabel/bar_normal_busy.png 
> 
> Despite both pictures saying micro-seconds at the respective
> axis (and hence the problem not being _as bad_)

This particular graph doesn't show it very well but there are small
blips around 4, 10, and 31 ms.

David

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