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Re: [PATCH v2] cfq-iosched: convert group idle time to jiffies

From Jens Axboe <axboe@kernel.dk>
Newsgroups linux.kernel
Subject Re: [PATCH v2] cfq-iosched: convert group idle time to jiffies
Date 2015-12-29 21:30 +0100
Message-ID <qL945-5iB-3@gated-at.bofh.it> (permalink)
References <qL8Uq-5fn-19@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On 12/29/2015 01:16 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 group_idle
> is 8ms.
>
> Since the time given by group_idle 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.

Again, the slice idle values are stored in jiffies, there's no need to 
convert. I think you are missing the fact that we display the value in 
msecs, and convert when displaying/storing through sysfs.

-- 
Jens Axboe

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Thread

[PATCH v2] cfq-iosched: convert group idle time to jiffies Alexandru Moise <00moses.alexander00@gmail.com> - 2015-12-29 21:20 +0100
  Re: [PATCH v2] cfq-iosched: convert group idle time to jiffies Jens Axboe <axboe@kernel.dk> - 2015-12-29 21:30 +0100
    Re: [PATCH v2] cfq-iosched: convert group idle time to jiffies Alexandru Moise <00moses.alexander00@gmail.com> - 2015-12-29 21:30 +0100

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