From: Paolo Valente <paolo.valente@linaro.org>
To: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>,
Fabio Checconi <fchecconi@gmail.com>,
Arianna Avanzini <avanzini.arianna@gmail.com>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
ulf.hansson@linaro.org, linus.walleij@linaro.org,
broonie@kernel.org
Subject: Re: [PATCH RFC 10/22] block, bfq: add full hierarchical scheduling and cgroups support
Date: Fri, 22 Apr 2016 21:05:14 +0200 [thread overview]
Message-ID: <C1A89D63-CBC4-4C92-8D5A-9FB55A53FBCF@linaro.org> (raw)
In-Reply-To: <20160422184110.GX7822@mtj.duckdns.org>
Il giorno 22/apr/2016, alle ore 20:41, Tejun Heo <tj@kernel.org> ha scritto:
> Hello, Paolo.
>
> On Fri, Apr 22, 2016 at 08:19:47PM +0200, Paolo Valente wrote:
>>> So, a kworker would jump through different workqueues and issue IOs
>>> for different writeback domains and the context can't be tied to the
>>> issuing task. The cgroup membership should be determined directly
>>> from the bio.
>>
>> Yes. My doubt arises from the fact that the only source of intense I/O
>> is the dd (I have executed it alone). In contrast, group changes occur
>> at a high frequency during all the execution of the dd. Apparently I
>> cannot see any other I/O induced by the dd. Journaling issues sync
>> requests.
>>
>>> cfq uses per-cgroup async queue. I'm not sure how this
>>> would map to bfq tho.
>>
>> It’s the same. But this is the part I’m checking.
>
> Ah, right, I was confused. cic is always associated with the task and
> yes a writeback worker can trigger blkcg changed events frequently as
> it walks through different cgroups. Is this an issue?
>
That’s exactly the source of my confusion: why does the worker walk through different cgroups all the time if the I/O is originated by the same process, which never changes group?
Thanks,
Paolo
> Thanks.
>
> --
> tejun
next prev parent reply other threads:[~2016-04-22 19:05 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-01 22:12 [PATCH RFC 00/22] Replace the CFQ I/O Scheduler with BFQ Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 01/22] block, cfq: remove queue merging for close cooperators Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 02/22] block, cfq: remove close-based preemption Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 03/22] block, cfq: remove deep seek queues logic Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 04/22] block, cfq: remove SSD-related logic Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 05/22] block, cfq: get rid of hierarchical support Paolo Valente
2016-02-10 23:04 ` Tejun Heo
2016-02-01 22:12 ` [PATCH RFC 06/22] block, cfq: get rid of queue preemption Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 07/22] block, cfq: get rid of workload type Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 08/22] block, cfq: get rid of latency tunables Paolo Valente
2016-02-10 23:05 ` Tejun Heo
2016-02-01 22:12 ` [PATCH RFC 09/22] block, cfq: replace CFQ with the BFQ-v0 I/O scheduler Paolo Valente
2016-02-11 22:22 ` Tejun Heo
2016-02-12 0:35 ` Mark Brown
2016-02-17 15:57 ` Tejun Heo
2016-02-17 16:02 ` Mark Brown
2016-02-17 17:04 ` Tejun Heo
2016-02-17 18:13 ` Jonathan Corbet
2016-02-17 19:45 ` Tejun Heo
2016-02-17 19:56 ` Jonathan Corbet
2016-02-17 20:14 ` Tejun Heo
2016-02-17 9:02 ` Paolo Valente
2016-02-17 17:02 ` Tejun Heo
2016-02-20 10:23 ` Paolo Valente
2016-02-20 11:02 ` Paolo Valente
2016-03-01 18:46 ` Tejun Heo
2016-03-04 17:29 ` Linus Walleij
2016-03-04 17:39 ` Christoph Hellwig
2016-03-04 18:10 ` Austin S. Hemmelgarn
2016-03-11 11:16 ` Christoph Hellwig
2016-03-11 13:38 ` Austin S. Hemmelgarn
2016-03-05 12:18 ` Linus Walleij
2016-03-11 11:17 ` Christoph Hellwig
2016-03-11 11:24 ` Nikolay Borisov
2016-03-11 11:49 ` Christoph Hellwig
2016-03-11 14:53 ` Linus Walleij
2016-03-09 6:55 ` Paolo Valente
2016-04-13 19:54 ` Tejun Heo
2016-04-14 5:03 ` Mark Brown
2016-03-09 6:34 ` Paolo Valente
2016-04-13 20:41 ` Tejun Heo
2016-04-14 10:23 ` Paolo Valente
2016-04-14 16:29 ` Tejun Heo
2016-04-15 14:20 ` Paolo Valente
2016-04-15 15:08 ` Tejun Heo
2016-04-15 16:17 ` Paolo Valente
2016-04-15 19:29 ` Tejun Heo
2016-04-15 22:08 ` Paolo Valente
2016-04-15 22:45 ` Tejun Heo
2016-04-16 6:03 ` Paolo Valente
2016-04-15 14:49 ` Linus Walleij
2016-02-01 22:12 ` [PATCH RFC 10/22] block, bfq: add full hierarchical scheduling and cgroups support Paolo Valente
2016-02-11 22:28 ` Tejun Heo
2016-02-17 9:07 ` Paolo Valente
2016-02-17 17:14 ` Tejun Heo
2016-02-17 17:45 ` Tejun Heo
2016-04-20 9:32 ` Paolo
2016-04-22 18:13 ` Tejun Heo
2016-04-22 18:19 ` Paolo Valente
2016-04-22 18:41 ` Tejun Heo
2016-04-22 19:05 ` Paolo Valente [this message]
2016-04-22 19:32 ` Tejun Heo
2016-04-23 7:07 ` Paolo Valente
2016-04-25 19:24 ` Tejun Heo
2016-04-25 20:30 ` Paolo
2016-05-06 20:20 ` Paolo Valente
2016-05-12 13:11 ` Paolo
2016-07-27 16:13 ` [PATCH RFC V8 00/22] Replace the CFQ I/O Scheduler with BFQ Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 01/22] block, cfq: remove queue merging for close cooperators Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 02/22] block, cfq: remove close-based preemption Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 03/22] block, cfq: remove deep seek queues logic Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 04/22] block, cfq: remove SSD-related logic Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 05/22] block, cfq: get rid of hierarchical support Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 06/22] block, cfq: get rid of queue preemption Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 07/22] block, cfq: get rid of workload type Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 08/22] block, cfq: get rid of latency tunables Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 09/22] block, cfq: replace CFQ with the BFQ-v0 I/O scheduler Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 10/22] block, bfq: add full hierarchical scheduling and cgroups support Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 11/22] block, bfq: improve throughput boosting Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 12/22] block, bfq: modify the peak-rate estimator Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 13/22] block, bfq: add more fairness with writes and slow processes Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 14/22] block, bfq: improve responsiveness Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 15/22] block, bfq: reduce I/O latency for soft real-time applications Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 16/22] block, bfq: preserve a low latency also with NCQ-capable drives Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 17/22] block, bfq: reduce latency during request-pool saturation Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 18/22] block, bfq: add Early Queue Merge (EQM) Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 19/22] block, bfq: reduce idling only in symmetric scenarios Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 20/22] block, bfq: boost the throughput on NCQ-capable flash-based devices Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 21/22] block, bfq: boost the throughput with random I/O on NCQ-capable HDDs Paolo Valente
2016-07-27 16:13 ` [PATCH RFC V8 22/22] block, bfq: handle bursts of queue activations Paolo Valente
2016-07-28 16:50 ` [PATCH RFC V8 00/22] Replace the CFQ I/O Scheduler with BFQ Paolo
2016-02-01 22:12 ` [PATCH RFC 11/22] block, bfq: improve throughput boosting Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 12/22] block, bfq: modify the peak-rate estimator Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 13/22] block, bfq: add more fairness to boost throughput and reduce latency Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 14/22] block, bfq: improve responsiveness Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 15/22] block, bfq: reduce I/O latency for soft real-time applications Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 16/22] block, bfq: preserve a low latency also with NCQ-capable drives Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 17/22] block, bfq: reduce latency during request-pool saturation Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 18/22] block, bfq: add Early Queue Merge (EQM) Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 19/22] block, bfq: reduce idling only in symmetric scenarios Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 20/22] block, bfq: boost the throughput on NCQ-capable flash-based devices Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 21/22] block, bfq: boost the throughput with random I/O on NCQ-capable HDDs Paolo Valente
2016-02-01 22:12 ` [PATCH RFC 22/22] block, bfq: handle bursts of queue activations Paolo Valente
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