Re: [PATCH] cfq-iosched: convert slice idle time to jiffies

From	Alexandru Moise <00moses.alexander00@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] cfq-iosched: convert slice idle time to jiffies
Date	2015-12-29 18:40 +0100
Message-ID	<qL6pB-3za-35@gated-at.bofh.it> (permalink)
References	<qKQXw-1JA-9@gated-at.bofh.it> <qL66f-3rU-21@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On Tue, Dec 29, 2015 at 10:19:17AM -0700, Jens Axboe wrote:
> On 12/28/2015 06:08 PM, Alexandru Moise wrote:
> >This patch refers to Jens Axboe's change way back in 2006:
> >7b14e3b52 cfq-iosched: slice expiry fixups
> >
> >In this patch he fixed a potential timer race condition by delaying
> >idle_slice_timer by the slice_idle time value.
> >
> >Today this timer is delayed by either slice_idle or group_idle time
> >values, which on my system, and according to
> >Documentation/block/cfq-iosched.txt the default value for both is 8ms.
> >
> >Since the time given by either variables is supposed to be in
> >milliseconds we should convert that value from milliseconds to jiffies
> >before adding it to jiffies variable and setting our timer.
> >
> >In my obervations the area is really active as I've seen that function
> >get called a lot for each device on my btrfs raid setup during btrfs
> >check. I've also timed the btrfs check before and after applying the
> >patch and I might've noticed a very slight improvement in execution
> >time but the numbers vary too much for me to post any believable
> >numbers (10 milliseconds difference at most on average).
> 
> cfqd->cfq_slice_idle is in jiffies, it's not in msecs.
> 
> -- 
> Jens Axboe
> 

Then should I only do the conversion in the case of group_idle?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Find similar | Unroll thread

Thread

[PATCH] cfq-iosched: convert slice idle time to jiffies Alexandru Moise <00moses.alexander00@gmail.com> - 2015-12-29 02:10 +0100
  Re: [PATCH] cfq-iosched: convert slice idle time to jiffies Jens Axboe <axboe@kernel.dk> - 2015-12-29 18:20 +0100
    Re: [PATCH] cfq-iosched: convert slice idle time to jiffies Alexandru Moise <00moses.alexander00@gmail.com> - 2015-12-29 18:40 +0100

csiph-web