From: Tejun Heo <tj@kernel.org>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org,
lizefan@huawei.com, containers@lists.linux-foundation.org,
cgroups@vger.kernel.org
Subject: Re: [PATCHSET] blk-throttle: implement proper hierarchy support
Date: Thu, 2 May 2013 10:57:01 -0700 [thread overview]
Message-ID: <20130502175701.GL19814@mtj.dyndns.org> (raw)
In-Reply-To: <20130502173428.GA4771@redhat.com>
Hey, Vivek.
On Thu, May 02, 2013 at 01:34:28PM -0400, Vivek Goyal wrote:
> On Wed, May 01, 2013 at 05:39:18PM -0700, Tejun Heo wrote:
>
> [..]
> > While this patchset contains many patches, the implementation is
> > pretty straight-forward. throtl_grp's form a tree anchored at
> > throtl_data and bios climb the tree as they get dispatched at each
> > level. The bios which reach the top of the tree - throl_data - are
> > issued.
>
> Have a question here. Looks like when bio climbs from child group
> to parent group, then parent group slice starts fresh if parent
> was empty. So if we have a parent with 1MB/s limit and a child with
> 1MB/s limit and a bio gets queued in child, then looks like effective
> IO rate would be .5MB/s and not 1MB/s?
Hmmm.... not that drastic but when the same limit is configured in
both parent and its single active child, the child gets penalized by
about 15%, which is not nice.
> IOW, when child gets queued, we should start time accounting for
> all parents in the hiearchy too.
I don't particularly like doing that as a separate step, maybe we can
just push the child's start time to the parent while dispatching?
Does that sound doable to you?
Thanks.
--
tejun
next prev parent reply other threads:[~2013-05-02 17:57 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-02 0:39 [PATCHSET] blk-throttle: implement proper hierarchy support Tejun Heo
2013-05-02 0:39 ` [PATCH 01/31] blkcg: fix error return path in blkg_create() Tejun Heo
2013-05-02 0:39 ` [PATCH 02/31] blkcg: move blkg_for_each_descendant_pre() to block/blk-cgroup.h Tejun Heo
2013-05-02 0:39 ` [PATCH 03/31] blkcg: implement blkg_for_each_descendant_post() Tejun Heo
2013-05-02 0:39 ` [PATCH 04/31] blkcg: invoke blkcg_policy->pd_init() after parent is linked Tejun Heo
2013-05-02 0:39 ` [PATCH 05/31] blkcg: move bulk of blkcg_gq release operations to the RCU callback Tejun Heo
2013-05-02 0:39 ` [PATCH 06/31] blk-throttle: remove spurious throtl_enqueue_tg() call from throtl_select_dispatch() Tejun Heo
2013-05-02 0:39 ` [PATCH 07/31] blk-throttle: removed deferred config application mechanism Tejun Heo
2013-05-02 14:49 ` Vivek Goyal
2013-05-02 17:27 ` Tejun Heo
2013-05-02 0:39 ` [PATCH 08/31] blk-throttle: collapse throtl_dispatch() into the work function Tejun Heo
2013-05-02 0:39 ` [PATCH 09/31] blk-throttle: relocate throtl_schedule_delayed_work() Tejun Heo
2013-05-02 0:39 ` [PATCH 10/31] blk-throttle: remove pointless throtl_nr_queued() optimizations Tejun Heo
2013-05-02 0:39 ` [PATCH 11/31] blk-throttle: rename throtl_rb_root to throtl_service_queue Tejun Heo
2013-05-02 0:39 ` [PATCH 12/31] blk-throttle: simplify throtl_grp flag handling Tejun Heo
2013-05-02 0:39 ` [PATCH 13/31] blk-throttle: add backlink pointer from throtl_grp to throtl_data Tejun Heo
2013-05-02 0:39 ` [PATCH 14/31] blk-throttle: pass around throtl_service_queue instead of throtl_data Tejun Heo
2013-05-02 0:39 ` [PATCH 15/31] blk-throttle: reorganize throtl_service_queue passed around as argument Tejun Heo
2013-05-02 15:21 ` Vivek Goyal
2013-05-02 17:29 ` Tejun Heo
2013-05-02 0:39 ` [PATCH 16/31] blk-throttle: add throtl_grp->service_queue Tejun Heo
2013-05-02 0:39 ` [PATCH 17/31] blk-throttle: move bio_lists[] and friends to throtl_service_queue Tejun Heo
2013-05-02 0:39 ` [PATCH 18/31] blk-throttle: dispatch to throtl_data->service_queue.bio_lists[] Tejun Heo
2013-05-02 0:39 ` [PATCH 19/31] blk-throttle: generalize update_disptime optimization in blk_throtl_bio() Tejun Heo
2013-05-02 0:39 ` [PATCH 20/31] blk-throttle: add throtl_service_queue->parent_sq Tejun Heo
2013-05-02 0:39 ` [PATCH 21/31] blk-throttle: implement sq_to_tg(), sq_to_td() and throtl_log() Tejun Heo
2013-05-06 17:36 ` Vivek Goyal
2013-05-06 18:38 ` Tejun Heo
2013-05-06 20:38 ` Tejun Heo
2013-05-06 20:39 ` Tejun Heo
2013-05-06 20:41 ` Vivek Goyal
2013-05-06 20:43 ` Tejun Heo
2013-05-02 0:39 ` [PATCH 22/31] blk-throttle: set REQ_THROTTLED from throtl_charge_bio() and gate stats update with it Tejun Heo
2013-05-02 0:39 ` [PATCH 23/31] blk-throttle: separate out throtl_service_queue->pending_timer from throtl_data->dispatch_work Tejun Heo
2013-05-02 0:39 ` [PATCH 24/31] blk-throttle: implement dispatch looping Tejun Heo
2013-05-02 0:39 ` [PATCH 25/31] blk-throttle: dispatch from throtl_pending_timer_fn() Tejun Heo
2013-05-02 0:39 ` [PATCH 26/31] blk-throttle: make blk_throtl_drain() ready for hierarchy Tejun Heo
2013-05-02 0:39 ` [PATCH 27/31] blk-throttle: make blk_throtl_bio() " Tejun Heo
2013-05-02 0:39 ` [PATCH 28/31] blk-throttle: make tg_dispatch_one_bio() " Tejun Heo
2013-05-02 0:39 ` [PATCH 29/31] blk-throttle: make throtl_pending_timer_fn() " Tejun Heo
2013-05-02 0:39 ` [PATCH 30/31] blk-throttle: implement throtl_grp->has_rules[] Tejun Heo
2013-05-02 0:39 ` [PATCH 31/31] blk-throttle: implement proper hierarchy support Tejun Heo
2013-05-02 17:34 ` [PATCHSET] " Vivek Goyal
2013-05-02 17:57 ` Tejun Heo [this message]
2013-05-02 18:17 ` Vivek Goyal
2013-05-02 18:29 ` Tejun Heo
2013-05-02 18:45 ` Vivek Goyal
2013-05-02 18:49 ` Tejun Heo
2013-05-02 19:07 ` Vivek Goyal
2013-05-02 19:11 ` Tejun Heo
2013-05-02 19:31 ` Vivek Goyal
2013-05-02 23:13 ` Tejun Heo
2013-05-03 17:56 ` Vivek Goyal
2013-05-03 18:57 ` Tejun Heo
2013-05-03 18:58 ` Tejun Heo
2013-05-03 19:08 ` Vivek Goyal
2013-05-03 19:14 ` Tejun Heo
2013-05-03 19:26 ` Vivek Goyal
2013-05-03 21:05 ` Vivek Goyal
2013-05-03 23:54 ` Tejun Heo
2013-05-06 17:33 ` Vivek Goyal
2013-05-02 18:08 ` Vivek Goyal
2013-05-02 18:44 ` Tejun Heo
2013-05-02 18:59 ` Vivek Goyal
2013-05-04 0:50 ` [PATCH 29.5/32] blk-throttle: add throtl_qnode for dispatch fairness Tejun Heo
2013-05-04 0:53 ` Tejun Heo
2013-05-06 16:00 ` Vivek Goyal
2013-05-06 18:35 ` Tejun Heo
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