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Re: [Qemu-block] I/O accounting overhaul
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From: |
Alberto Garcia |
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Subject: |
Re: [Qemu-block] I/O accounting overhaul |
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Date: |
Wed, 10 Jun 2015 13:41:53 +0200 |
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User-agent: |
Notmuch/0.13.2 (http://notmuchmail.org) Emacs/23.2.1 (i486-pc-linux-gnu) |
On Mon 08 Jun 2015 03:21:19 PM CEST, Stefan Hajnoczi <address@hidden> wrote:
> Please structure the patches so that each statistic or group of
> statistics has its own patch.
Yes, that's the plan.
>> uint64_t queue_depth[BLOCK_MAX_IOTYPE];
>>
>> Average number of requests. Similar to the previous one. It would
>> require us to keep a count of ongoing requests as well.
>
> How is this calculated?
>
> You can keep track of the maximum queue depth easily (I think that's
> what fio does, for example). For anything else you need a concept of
> time like a load average calculation.
We already need a way to compute the average latency for I/O operations
in a certain period of time, so we can use that. Benoît had already
written some code for that purpose and that's what I'm using as the
basis for my work.
https://lists.nongnu.org/archive/html/qemu-devel/2014-09/msg04844.html
Berto