Il giorno 16 mag 2017, alle ore 15:22, Sedat Dilek =

[off-list ref] ha scritto:

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On Tue, May 16, 2017 at 10:45 AM, Paolo Valente
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Il giorno 13 mag 2017, alle ore 09:50, Sedat Dilek =

[off-list ref] ha scritto:

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On Wed, May 3, 2017 at 11:21 AM, Paolo Valente =

[off-list ref] wrote:

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Il giorno 03 mag 2017, alle ore 10:00, Sedat Dilek =

[off-list ref] ha scritto:

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On Tue, May 2, 2017 at 2:16 PM, Markus Trippelsdorf
[off-list ref] wrote:

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On 2017.05.02 at 14:07 +0200, Sedat Dilek wrote:

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On Tue, May 2, 2017 at 10:00 AM, Markus Trippelsdorf
[off-list ref] wrote:

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On 2017.05.02 at 09:54 +0200, Sedat Dilek wrote:

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Hi,
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I want to play with BFQ.
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My base is block-next as of 28-Apr-2017.

[...]

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Not sure if the attached patches make sense (right now).

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No, it doesn't make sense at all.

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Hmm, I looked at 4.11.0-v8r11 and 0001 has exactly what my 2 =

patches do :-).

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BFQ started as a conventional scheduler. But because mq is the =

way of

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the future it was ported before it was accepted into mainline.
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I am still playing and want to do my own experiences with BFQ.
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Not sure if FIO is a good testcase-tool here.
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If you want to perform a thorough benchmarking of also =

responsiveness

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and latency for time-sensitive applications (such as video playing)
then you may want to use S [1].  It's rather rustic, do ask if you
encounter any difficulty.
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[1] https://github.com/Algodev-github/S
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Sorry for the delay.

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Don't worry, I'm replying late too ...
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Currently, I am swittching from Ubuntu/precise 12.04 LTS (EOL) back =

to

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the Debian world.
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The responsiveness is really bad when my mlocate cron-job, a git =

pull

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on linux.git and firefox runs parallel.

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Thanks for reporting this issue.  I have a few considerations and
requests for information on it.
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1) Two of the three sources of I/O you mention, namely mlocate update
and git pull, are doing writes.  As I already pointed in a few
occasions and places, intense write workloads trigger problems that =

an

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I/O scheduler cannot solve.  In contrast, these problems *can* be
solved using BFQ.  In particular, I already have a prototype =

solution,

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but I have't found support yet to turn it into a possible
production-level solution;  till a few days, ago, when I talked about
this with Goldwyn Rodrigues (in CC). He seems interested in having a
look at this solution, and possibly collaborating on it.
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2) A web browser like Firefox can generate extremely varying
workloads; so, if you mentioned Firefox as one of the sources of I/O
in your unlucky situation, then it would be important to know what
Firefox was doing.
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3) Even if BFQ cannot counteract problems occurring above its head, =

it

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usually improves responsiveness even in heavy-write scenarios.  It
would then be interesting if you could compare responsiveness with =

the

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other I/O schedulers (mq-deadline, Kyber) and with none too (make =

sure

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that the I/O is really the same in all cases).
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Not willing to test on this dead horse called Ubuntu 12.04.
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This is with Linux v4.11.1-rc1 and BFQ patchset v4.11.0-v8r11.
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My linux-config is attached.
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So if MQ is the way why isn't the Kconfig called =

CONFIG_MQ_IOSCHED_BFQ

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according to CONFIG_MQ_IOSCHED_DEADLINE?
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As we are talking about "*Storage* I/O schedulers" which of the MQ
Kconfig make sense when using MQ_DEADLINE and (MQ_)BFQ?
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# egrep -i 'bfq|deadline|_mq|mq_|_mq_' =

/boot/config-4.11.0-1-bfq-amd64

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CONFIG_POSIX_MQUEUE=3Dy
CONFIG_POSIX_MQUEUE_SYSCTL=3Dy
CONFIG_BLK_WBT_MQ=3Dy
CONFIG_BLK_MQ_PCI=3Dy
CONFIG_BLK_MQ_VIRTIO=3Dy
CONFIG_IOSCHED_DEADLINE=3Dy
CONFIG_IOSCHED_BFQ=3Dy
CONFIG_BFQ_GROUP_IOSCHED=3Dy
# CONFIG_DEFAULT_DEADLINE is not set
CONFIG_DEFAULT_BFQ=3Dy
CONFIG_DEFAULT_IOSCHED=3D"bfq"
CONFIG_MQ_IOSCHED_DEADLINE=3Dy
# CONFIG_NET_SCH_MQPRIO is not set
CONFIG_SCSI_MQ_DEFAULT=3Dy
# CONFIG_DM_MQ_DEFAULT is not set
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The config for BFQ seems correct.  For the others, it depends on =

what

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scheduler you want.  If useful for you, the other two MQ- =

schedulers

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are mq-deadline and cyber.
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What about those two (Kconfig) patches which is in your current
bfq-4.11.y patchset.
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I'm not sure I fully understand the purpose of the two patches you
propose (in your following emails).  The first patch seems to move =

BFQ

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config options to a different position in Kconfig.iosched, but the
position of those items should be irrelevant.  Am I missing =

something?

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The second patch seems to have to do with configuration bits of bfq
for blk, yet such a bfq version is not available in mainline.
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In any case, for possible new submissions, you should inline your
patches.  For complete instructions on submitting patches, have a =

look

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at Documentation/process/submitting-patches
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All my testings was done with your patchset against Linux v4.11.y.
You have the same kconfig/kbuild stuff in your 0001 patch [1], so :-)?
What you have in 0001 is missing in Linux v4.12-rc1.
Not sure if this is intended.

4.12-rc1 contains bfq for blk-mq, while the patch you mention is for
bfq for blk (never accepted in mainline).  Maybe you could get a
clearer idea by having a look at the commits that add bfq (for blk-mq)
in 4.12-rc1.

Hope this helps,
Paolo

I will re-submit and add a "4.12" in the subject-line when I am at =

home.

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- Sedat -
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[1] =

http://algo.ing.unimo.it/people/paolo/disk_sched/patches/4.11.0-v8r11/0001=
-block-cgroups-kconfig-build-bits-for-BFQ-v7r11-4.11..patch