Re: A thought about IO scheduler in linux kernel for SSD

From: 韩磊
Date: Thu Oct 24 2013 - 23:10:31 EST

2013/10/23 Jan Kara <jack@xxxxxxx>:
> On Wed 23-10-13 08:47:44, 韩磊 wrote:
>> Nowadays,the IO schedulers in linux kernel have four types:
>> deadline,noop,Anticiptory and CFQ.CFQ is the default scheduler.But CFQ is
>> not a good scheduler for SSD,dealine may be a good choice.
> That doesn't make much sense to me. If there are two bios in flight for
> some sector, results are undefined. Thus we usually avoid such situation
> (usually we want to have defined contents of the disk :). The exclusion is
> usually achieved at higher level using page locking etc. So adding code
> speeding up such requests doesn't seem worth it.
> Honza
> --
> Jan Kara <jack@xxxxxxx>
> SUSE Labs, CR

Do you mean that the probability of two bios have the same start
sector in request list at this level is very low??Discuss with you
is a kind of enjoyment.
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