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Re: [Qemu-devel] [Qemu-block] [PATCH 00/13] throttle: Allow I/O bursts f
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [Qemu-block] [PATCH 00/13] throttle: Allow I/O bursts for a user-defined period of time |
Date: |
Mon, 15 Feb 2016 16:40:29 +0000 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Fri, Feb 05, 2016 at 12:59:10PM +0200, Alberto Garcia wrote:
> - With this series we set "a maximum of X operations/second for a
> period of T seconds". If would also be possible to make it "a
> maximum of X operations/second up to a total of Y operations". It
> would be equivalent (Y = X * T) but I thought the current proposal
> makes a more clear API.
I find the diagram in the blog post clear. The QEMU code is a little
harder to understand, it seems like there are too many variables and
special cases. There are 4 core variables:
1. Refill rate (aka avg), e.g. 30 IOPS
2. Max bucket level (aka max * burst_length), e.g. 5.4 million IOPS
3. Burst rate (aka max), e.g. 3000 IOPS
4. Current bucket level
However, your patch to the core algorithm is small and makes sense to
me. Maybe I just don't appreciate some of the subtleties that require
the existing code to use more variables.
Looks good to me.
Reviewed-by: Stefan Hajnoczi <address@hidden>
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- [Qemu-devel] [PATCH 07/13] throttle: Use throttle_config_init() to initialize ThrottleConfig, (continued)
- [Qemu-devel] [PATCH 07/13] throttle: Use throttle_config_init() to initialize ThrottleConfig, Alberto Garcia, 2016/02/05
- [Qemu-devel] [PATCH 08/13] throttle: Add support for burst periods, Alberto Garcia, 2016/02/05
- [Qemu-devel] [PATCH 11/13] qapi: Add burst length fields to BlockDeviceInfo, Alberto Garcia, 2016/02/05
- [Qemu-devel] [PATCH 13/13] throttle: Test throttle_compute_wait() during bursts, Alberto Garcia, 2016/02/05
- [Qemu-devel] [PATCH 03/13] throttle: Make throttle_max_is_missing_limit() set errp, Alberto Garcia, 2016/02/05
- [Qemu-devel] [PATCH 10/13] qapi: Add burst length parameters to block_set_io_throttle, Alberto Garcia, 2016/02/05
- Re: [Qemu-devel] [PATCH 00/13] throttle: Allow I/O bursts for a user-defined period of time, Kevin Wolf, 2016/02/12
- Re: [Qemu-devel] [Qemu-block] [PATCH 00/13] throttle: Allow I/O bursts for a user-defined period of time,
Stefan Hajnoczi <=