From: "Benoît Canet" <benoit.canet@irqsave.net>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: kwolf@redhat.com, wuzhy@linux.vnet.ibm.com,
qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] block: fix bdrv_exceed_iops_limits wait computation
Date: Wed, 20 Mar 2013 15:56:33 +0100 [thread overview]
Message-ID: <20130320145633.GA1473@irqsave.net> (raw)
In-Reply-To: <20130320142842.GA2389@stefanha-thinkpad.muc.redhat.com>
> But I don't understand why bs->slice_time is modified instead of keeping
> it constant at 100 ms:
>
> bs->slice_time = wait_time * BLOCK_IO_SLICE_TIME * 10;
> bs->slice_end += bs->slice_time - 3 * BLOCK_IO_SLICE_TIME;
> if (wait) {
> *wait = wait_time * BLOCK_IO_SLICE_TIME * 10;
> }
In bdrv_exceed_bps_limits there is an equivalent to this with a comment.
---------
/* When the I/O rate at runtime exceeds the limits,
* bs->slice_end need to be extended in order that the current statistic
* info can be kept until the timer fire, so it is increased and tuned
* based on the result of experiment.
*/
bs->slice_time = wait_time * BLOCK_IO_SLICE_TIME * 10;
bs->slice_end += bs->slice_time - 3 * BLOCK_IO_SLICE_TIME;
if (wait) {
*wait = wait_time * BLOCK_IO_SLICE_TIME * 10;
}
----------
Yes I will try your patch.
Regards
Benoît
next prev parent reply other threads:[~2013-03-20 14:55 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-20 9:12 [Qemu-devel] [PATCH] Fix I/O throttling pathologic oscillating behavior Benoît Canet
2013-03-20 9:12 ` [Qemu-devel] [PATCH] block: fix bdrv_exceed_iops_limits wait computation Benoît Canet
2013-03-20 10:55 ` Zhi Yong Wu
2013-03-20 13:29 ` Stefan Hajnoczi
2013-03-20 14:28 ` Stefan Hajnoczi
2013-03-20 14:56 ` Benoît Canet [this message]
2013-03-20 15:12 ` Stefan Hajnoczi
2013-03-21 1:18 ` Zhi Yong Wu
2013-03-21 9:17 ` Stefan Hajnoczi
2013-03-21 13:04 ` Zhi Yong Wu
2013-03-21 15:14 ` Stefan Hajnoczi
2013-03-20 15:27 ` Benoît Canet
2013-03-21 10:34 ` Stefan Hajnoczi
2013-03-21 14:28 ` Benoît Canet
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