linux-kernel - Re: [PATCH V5 08/17] blk-throttle: make throtl

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20170109200843.GL12827@mtj.duckdns.org>
Date:   Mon, 9 Jan 2017 15:08:43 -0500
From:   Tejun Heo <tj@...nel.org>
To:     Shaohua Li <shli@...com>
Cc:     linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-team@...com, axboe@...com, vgoyal@...hat.com
Subject: Re: [PATCH V5 08/17] blk-throttle: make throtl_slice tunable

Hello,

On Thu, Dec 15, 2016 at 12:32:59PM -0800, Shaohua Li wrote:
> throtl_slice is important for blk-throttling. It's called slice
> internally but it really is a time window blk-throttling samples data.
> blk-throttling will make decision based on the samplings. An example is
> bandwidth measurement. A cgroup's bandwidth is measured in the time
> interval of throtl_slice.
> 
> A small throtl_slice meanse cgroups have smoother throughput but burn
> more CPUs. It has 100ms default value, which is not appropriate for all
> disks. A fast SSD can dispatch a lot of IOs in 100ms. This patch makes
> it tunable.
> 
> Since throtl_slice isn't a time slice, the sysfs name
> 'throttle_sample_time' reflects its character better.

Generally looks good.  I think some documentation would be great.
Also, do we wannt set it to a lower number if blk_queue_nonrot()?

Thanks.

-- 
tejun