From: Tao Ma <tm@tao.ma>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: Shaohua Li <shli@kernel.org>, Tejun Heo <tj@kernel.org>,
axboe@kernel.dk, ctalbott@google.com, rni@google.com,
linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
containers@lists.linux-foundation.org
Subject: Re: IOPS based scheduler (Was: Re: [PATCH 18/21] blkcg: move blkio_group_conf->weight to cfq)
Date: Thu, 05 Apr 2012 01:18:05 +0800 [thread overview]
Message-ID: <4F7C824D.2050308@tao.ma> (raw)
In-Reply-To: <20120404165048.GF12676@redhat.com>
On 04/05/2012 12:50 AM, Vivek Goyal wrote:
> On Thu, Apr 05, 2012 at 12:45:05AM +0800, Tao Ma wrote:
>
> [..]
>>> In iops_mode(), expire each cfqq after dispatch of 1 or bunch of requests
>>> and you should get the same behavior (with slice_idle=0 and group_idle=0).
>>> So why write a new scheduler.
>> really? How could we config cfq to work like this? Or you mean we can
>> change the code for it?
>
> You can just put a few lines of code to expire queue after 1-2 requests
> dispatched from the queue. Than run your workload with slice_idle=0
> and group_idle=0 and see what happens.
oh, yes I can do this to see whether the latency helps, but it is
hacking and doesn't work with the cgroup proportion...
>
> I don't even know what your workload is.
Sorry for not allowing to say more about it.
>
>>>
>>> Only thing is that with above, current code will provide iops fairness only
>>> for groups. We should be able to tweak queue scheduling to support iops
>>> fairness also.
>> OK, as I have said in another e-mail another my concern is the
>> complexity. It will make cfq too much complicated. I just checked the
>> source code of shaohua's original patch, fiops scheduler is only ~700
>> lines, so with cgroup support added it would be ~1000 lines I guess.
>> Currently cfq-iosched.c is around ~4000 lines even after Tejun's cleanup
>> of io context...
>
> I think a large chunk of that iops scheduler code will be borrowed from
> CFQ code. All the cgroup logic, queue creation logic, group scheduling
> logic etc. And that's the reason I was still exploring the possibility
> of having common code base.
Yeah, actually I was thinking of abstracting a generic logic, but it
seems a lot bit hard. Maybe we can try to unify the code later?
Thanks
Tao
next prev parent reply other threads:[~2012-04-04 17:18 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-28 22:51 [PATCHSET] block: modularize blkcg config and stat file handling Tejun Heo
2012-03-28 22:51 ` [PATCH 01/21] blkcg: remove unused @pol and @plid parameters Tejun Heo
2012-03-28 22:51 ` [PATCH 02/21] blkcg: BLKIO_STAT_CPU_SECTORS doesn't have subcounters Tejun Heo
2012-03-28 22:51 ` [PATCH 03/21] blkcg: introduce blkg_stat and blkg_rwstat Tejun Heo
2012-03-28 22:51 ` [PATCH 04/21] blkcg: restructure statistics printing Tejun Heo
2012-03-28 22:51 ` [PATCH 05/21] blkcg: drop blkiocg_file_write_u64() Tejun Heo
2012-03-28 22:51 ` [PATCH 06/21] blkcg: restructure configuration printing Tejun Heo
2012-03-28 22:51 ` [PATCH 07/21] blkcg: restructure blkio_group configruation setting Tejun Heo
2012-03-28 22:51 ` [PATCH 08/21] blkcg: blkg_conf_prep() Tejun Heo
2012-03-28 22:53 ` Tejun Heo
2012-03-28 22:51 ` [PATCH 09/21] blkcg: export conf/stat helpers to prepare for reorganization Tejun Heo
2012-03-28 22:51 ` [PATCH 10/21] blkcg: implement blkio_policy_type->cftypes Tejun Heo
2012-03-28 22:51 ` [PATCH 11/21] blkcg: move conf/stat file handling code to policies Tejun Heo
2012-03-28 22:51 ` [PATCH 12/21] cfq: collapse cfq.h into cfq-iosched.c Tejun Heo
2012-03-28 22:51 ` [PATCH 13/21] blkcg: move statistics update code to policies Tejun Heo
2012-03-28 22:51 ` [PATCH 14/21] blkcg: cfq doesn't need per-cpu dispatch stats Tejun Heo
2012-03-28 22:51 ` [PATCH 15/21] blkcg: add blkio_policy_ops operations for exit and stat reset Tejun Heo
2012-03-28 22:51 ` [PATCH 16/21] blkcg: move blkio_group_stats to cfq-iosched.c Tejun Heo
2012-03-28 22:51 ` [PATCH 17/21] blkcg: move blkio_group_stats_cpu and friends to blk-throttle.c Tejun Heo
2012-03-28 22:51 ` [PATCH 18/21] blkcg: move blkio_group_conf->weight to cfq Tejun Heo
2012-04-01 21:09 ` Vivek Goyal
2012-04-01 21:22 ` Tejun Heo
2012-04-02 21:39 ` Tao Ma
2012-04-02 21:49 ` Tejun Heo
2012-04-02 22:03 ` Tao Ma
2012-04-02 22:17 ` Tejun Heo
2012-04-02 22:20 ` Tao Ma
2012-04-02 22:25 ` Vivek Goyal
2012-04-02 22:28 ` Tejun Heo
2012-04-02 22:41 ` Tao Ma
2012-04-03 15:37 ` IOPS based scheduler (Was: Re: [PATCH 18/21] blkcg: move blkio_group_conf->weight to cfq) Vivek Goyal
2012-04-03 16:36 ` Tao Ma
2012-04-03 16:50 ` Vivek Goyal
2012-04-03 17:26 ` Tao Ma
2012-04-04 12:35 ` Shaohua Li
2012-04-04 13:37 ` Vivek Goyal
2012-04-04 14:52 ` Shaohua Li
2012-04-04 15:10 ` Vivek Goyal
2012-04-04 16:06 ` Tao Ma
2012-04-04 16:45 ` Tao Ma
2012-04-04 16:50 ` Vivek Goyal
2012-04-04 17:17 ` Vivek Goyal
2012-04-04 17:18 ` Tao Ma [this message]
2012-04-04 17:27 ` Vivek Goyal
2012-04-04 18:22 ` Vivek Goyal
2012-04-04 18:36 ` Tao Ma
2012-04-04 13:31 ` Vivek Goyal
2012-03-28 22:51 ` [PATCH 19/21] blkcg: move blkio_group_conf->iops and ->bps to blk-throttle Tejun Heo
2012-03-28 22:51 ` [PATCH 20/21] blkcg: pass around pd->pdata instead of pd itself in prfill functions Tejun Heo
2012-03-28 22:51 ` [PATCH 21/21] blkcg: drop BLKCG_STAT_{PRIV|POL|OFF} macros Tejun Heo
2012-03-29 8:18 ` [PATCHSET] block: modularize blkcg config and stat file handling Jens Axboe
2012-04-02 20:02 ` Tejun Heo
2012-04-02 21:51 ` Jens Axboe
2012-04-02 22:33 ` Tejun Heo
2012-04-01 19:38 ` Vivek Goyal
2012-04-01 21:42 ` Tejun Heo
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