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From: Tejun Heo <tj@kernel.org>
To: Paolo Valente <paolo.valente@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>,
	newella@fb.com, clm@fb.com, Josef Bacik <josef@toxicpanda.com>,
	dennisz@fb.com, Li Zefan <lizefan@huawei.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	linux-block <linux-block@vger.kernel.org>,
	kernel-team@fb.com, cgroups@vger.kernel.org, ast@kernel.org,
	daniel@iogearbox.net, kafai@fb.com, songliubraving@fb.com,
	yhs@fb.com, bpf@vger.kernel.org
Subject: Re: [PATCHSET block/for-next] IO cost model based work-conserving porportional controller
Date: Fri, 6 Sep 2019 07:58:26 -0700
Message-ID: <20190906145826.GL2263813@devbig004.ftw2.facebook.com> (raw)
In-Reply-To: <EFFA2298-8614-4AFC-9208-B36976F6548C@linaro.org>

Hello, Paolo.

On Fri, Sep 06, 2019 at 11:07:17AM +0200, Paolo Valente wrote:
> email.  As for the filesystem, I'm interested in ext4, because it is
> the most widely used file system, and, with some workloads, it makes

Ext4 can't do writeback control as it currently stands.  It creates
hard ordering across data writes from different cgroups.  No matter
what mechanism you use for IO control, it is broken.  I'm sure it's
fixable but does need some work.

That said, read-only tests like you're doing should work fine on ext4
too but the last time I tested io control on ext4 is more than a year
ago so something might have changed in the meantime.

Just to rule out this isn't what you're hitting.  Can you please run
your test on btrfs with the following patchset applied?

 http://lkml.kernel.org/r/20190710192818.1069475-1-tj@kernel.org

And as I wrote in the previous reply, I did run your benchmark on one
of the test machines and it did work fine.

Thanks.

-- 
tejun

      reply index

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-14  1:56 Tejun Heo
2019-06-14  1:56 ` [PATCH 01/10] blkcg: pass @q and @blkcg into blkcg_pol_alloc_pd_fn() Tejun Heo
2019-06-14  1:56 ` [PATCH 02/10] blkcg: make ->cpd_init_fn() optional Tejun Heo
2019-06-14  1:56 ` [PATCH 03/10] blkcg: separate blkcg_conf_get_disk() out of blkg_conf_prep() Tejun Heo
2019-06-14  1:56 ` [PATCH 04/10] block/rq_qos: add rq_qos_merge() Tejun Heo
2019-06-14  1:56 ` [PATCH 05/10] block/rq_qos: implement rq_qos_ops->queue_depth_changed() Tejun Heo
2019-06-14  1:56 ` [PATCH 06/10] blkcg: s/RQ_QOS_CGROUP/RQ_QOS_LATENCY/ Tejun Heo
2019-06-14  1:56 ` [PATCH 07/10] blk-mq: add optional request->pre_start_time_ns Tejun Heo
2019-06-14  1:56 ` [PATCH 08/10] blkcg: implement blk-ioweight Tejun Heo
2019-06-14 12:17   ` Toke Høiland-Jørgensen
2019-06-14 15:09     ` Tejun Heo
2019-06-14 20:50       ` Toke Høiland-Jørgensen
2019-06-15 15:57         ` Tejun Heo
2019-06-14  1:56 ` [PATCH 09/10] blkcg: add tools/cgroup/monitor_ioweight.py Tejun Heo
2019-06-14  1:56 ` [PATCH 10/10] blkcg: implement BPF_PROG_TYPE_IO_COST Tejun Heo
2019-06-14 11:32   ` Quentin Monnet
2019-06-14 14:52     ` Tejun Heo
2019-06-14 16:35       ` Alexei Starovoitov
2019-06-14 17:09         ` Tejun Heo
2019-06-14 17:56 ` [PATCHSET block/for-next] IO cost model based work-conserving porportional controller Tejun Heo
2019-08-20 10:48   ` Paolo Valente
2019-08-20 15:04     ` Paolo Valente
2019-08-20 15:19       ` Tejun Heo
2019-08-22  8:58         ` Paolo Valente
2019-08-31  6:53           ` Tejun Heo
2019-08-31  7:10             ` Paolo Valente
2019-08-31 11:20               ` Tejun Heo
2019-09-02 15:45             ` Paolo Valente
2019-09-02 15:56               ` Tejun Heo
2019-09-02 19:43                 ` Paolo Valente
2019-09-05 16:55                   ` Tejun Heo
2019-09-06  9:07                     ` Paolo Valente
2019-09-06 14:58                       ` Tejun Heo [this message]

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