From: Kashyap Desai <kashyap.desai@broadcom.com>
To: John Garry <john.garry@huawei.com>, Ming Lei <ming.lei@redhat.com>
Cc: axboe@kernel.dk, jejb@linux.ibm.com, martin.petersen@oracle.com,
don.brace@microsemi.com, Sumit Saxena <sumit.saxena@broadcom.com>,
bvanassche@acm.org, hare@suse.com, hch@lst.de,
Shivasharan Srikanteshwara
<shivasharan.srikanteshwara@broadcom.com>,
linux-block@vger.kernel.org, linux-scsi@vger.kernel.org,
esc.storagedev@microsemi.com, chenxiang66@hisilicon.com,
"PDL,MEGARAIDLINUX" <megaraidlinux.pdl@broadcom.com>
Subject: RE: [PATCH RFC v7 00/12] blk-mq/scsi: Provide hostwide shared tags for SCSI HBAs
Date: Sat, 13 Jun 2020 00:17:37 +0530 [thread overview]
Message-ID: <bbdec3b3fbeb9907d2ec66a2afa56c29@mail.gmail.com> (raw)
In-Reply-To: <c033f445-97fd-6dc9-c270-9890681b39d9@huawei.com>
> On 11/06/2020 04:07, Ming Lei wrote:
> >> Using 12x SAS SSDs on hisi_sas v3 hw. mq-deadline results are
> >> included, but it is not always an appropriate scheduler to use.
> >>
> >> Tag depth 4000 (default) 260**
> >>
> >> Baseline:
> >> none sched: 2290K IOPS 894K
> >> mq-deadline sched: 2341K IOPS 2313K
> >>
> >> Final, host_tagset=0 in LLDD*
> >> none sched: 2289K IOPS 703K
> >> mq-deadline sched: 2337K IOPS 2291K
> >>
> >> Final:
> >> none sched: 2281K IOPS 1101K
> >> mq-deadline sched: 2322K IOPS 1278K
> >>
> >> * this is relevant as this is the performance in supporting but not
> >> enabling the feature
> >> ** depth=260 is relevant as some point where we are regularly waiting
> >> for
> >> tags to be available. Figures were are a bit unstable here for
> >> testing.
John -
I tried V7 series and debug further on mq-deadline interface. This time I
have used another setup since HDD based setup is not readily available for
me.
In fact, I was able to simulate issue very easily using single scsi_device
as well. BTW, this is not an issue with this RFC, but generic issue.
Since I have converted nr_hw_queue > 1 for Broadcom product using this RFC,
It becomes noticeable now.
Problem - Using below command I see heavy CPU utilization on "
native_queued_spin_lock_slowpath". This is because kblockd work queue is
submitting IO from all the CPUs even though fio is bound to single CPU.
Lock contention from " dd_dispatch_request" is causing this issue.
numactl -C 13 fio
single.fio --iodepth=32 --bs=4k --rw=randread --ioscheduler=none --numjobs=1
--cpus_allowed_policy=split --ioscheduler=mq-deadline
--group_reporting --filename=/dev/sdd
While running above command, ideally we expect only kworker/13 to be active.
But you can see below - All the CPU is attempting submission and lots of CPU
consumption is due to lock contention.
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
2726 root 0 -20 0 0 0 R 56.5 0.0 0:53.20
kworker/13:1H-k
7815 root 20 0 712404 15536 2228 R 43.2 0.0 0:05.03 fio
2792 root 0 -20 0 0 0 I 26.6 0.0 0:22.19
kworker/18:1H-k
2791 root 0 -20 0 0 0 I 19.9 0.0 0:17.17
kworker/19:1H-k
1419 root 0 -20 0 0 0 I 19.6 0.0 0:17.03
kworker/20:1H-k
2793 root 0 -20 0 0 0 I 18.3 0.0 0:15.64
kworker/21:1H-k
1424 root 0 -20 0 0 0 I 17.3 0.0 0:14.99
kworker/22:1H-k
2626 root 0 -20 0 0 0 I 16.9 0.0 0:14.68
kworker/26:1H-k
2794 root 0 -20 0 0 0 I 16.9 0.0 0:14.87
kworker/23:1H-k
2795 root 0 -20 0 0 0 I 16.9 0.0 0:14.81
kworker/24:1H-k
2797 root 0 -20 0 0 0 I 16.9 0.0 0:14.62
kworker/27:1H-k
1415 root 0 -20 0 0 0 I 16.6 0.0 0:14.44
kworker/30:1H-k
2669 root 0 -20 0 0 0 I 16.6 0.0 0:14.38
kworker/31:1H-k
2796 root 0 -20 0 0 0 I 16.6 0.0 0:14.74
kworker/25:1H-k
2799 root 0 -20 0 0 0 I 16.6 0.0 0:14.56
kworker/28:1H-k
1425 root 0 -20 0 0 0 I 16.3 0.0 0:14.21
kworker/34:1H-k
2746 root 0 -20 0 0 0 I 16.3 0.0 0:14.33
kworker/32:1H-k
2798 root 0 -20 0 0 0 I 16.3 0.0 0:14.50
kworker/29:1H-k
2800 root 0 -20 0 0 0 I 16.3 0.0 0:14.27
kworker/33:1H-k
1423 root 0 -20 0 0 0 I 15.9 0.0 0:14.10
kworker/54:1H-k
1784 root 0 -20 0 0 0 I 15.9 0.0 0:14.03
kworker/55:1H-k
2801 root 0 -20 0 0 0 I 15.9 0.0 0:14.15
kworker/35:1H-k
2815 root 0 -20 0 0 0 I 15.9 0.0 0:13.97
kworker/56:1H-k
1484 root 0 -20 0 0 0 I 15.6 0.0 0:13.90
kworker/57:1H-k
1485 root 0 -20 0 0 0 I 15.6 0.0 0:13.82
kworker/59:1H-k
1519 root 0 -20 0 0 0 I 15.6 0.0 0:13.64
kworker/62:1H-k
2315 root 0 -20 0 0 0 I 15.6 0.0 0:13.87
kworker/58:1H-k
2627 root 0 -20 0 0 0 I 15.6 0.0 0:13.69
kworker/61:1H-k
2816 root 0 -20 0 0 0 I 15.6 0.0 0:13.75
kworker/60:1H-k
I root cause this issue -
Block layer always queue IO on hctx context mapped to CPU-13, but hw queue
run from all the hctx context.
I noticed in my test hctx48 has queued all the IOs. No other hctx has queued
IO. But all the hctx is counting for "run".
# cat hctx48/queued
2087058
#cat hctx*/run
151318
30038
83110
50680
69907
60391
111239
18036
33935
91648
34582
22853
61286
19489
Below patch has fix - "Run the hctx queue for which request was completed
instead of running all the hardware queue."
If this looks valid fix, please include in V8 OR I can post separate patch
for this. Just want to have some level of review from this discussion.
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 0652acd..f52118f 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -554,6 +554,7 @@ static bool scsi_end_request(struct request *req,
blk_status_t error,
struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
struct scsi_device *sdev = cmd->device;
struct request_queue *q = sdev->request_queue;
+ struct blk_mq_hw_ctx *mq_hctx = req->mq_hctx;
if (blk_update_request(req, error, bytes))
return true;
@@ -595,7 +596,8 @@ static bool scsi_end_request(struct request *req,
blk_status_t error,
!list_empty(&sdev->host->starved_list))
kblockd_schedule_work(&sdev->requeue_work);
else
- blk_mq_run_hw_queues(q, true);
+ blk_mq_run_hw_queue(mq_hctx, true);
+ //blk_mq_run_hw_queues(q, true);
percpu_ref_put(&q->q_usage_counter);
return false;
After above patch - Only kworker/13 is actively doing submission.
3858 root 0 -20 0 0 0 I 22.9 0.0 3:24.04
kworker/13:1H-k
16768 root 20 0 712008 14968 2180 R 21.6 0.0 0:03.27 fio
16769 root 20 0 712012 14968 2180 R 21.6 0.0 0:03.27 fio
Without above patch - 24 SSD driver can give 1.5M IOPS and after above patch
3.2M IOPS.
I will continue my testing.
Thanks, Kashyap
> >>
> >> A copy of the patches can be found here:
> >> https://github.com/hisilicon/kernel-dev/commits/private-topic-blk-mq-
> >> shared-tags-rfc-v7
> >>
> >> And to progress this series, we the the following to go in first, when
> >> ready:
> >> https://lore.kernel.org/linux-scsi/20200430131904.5847-1-hare@suse.de
> >> /
> > I'd suggest to add options to enable shared tags for null_blk &
> > scsi_debug in V8, so that it is easier to verify the changes without
> > real
> hardware.
> >
>
> ok, fine, I can look at including that. To stop the series getting too
> large, I
> might spin off the early patches, which are not strictly related.
>
> Thanks,
> John
next prev parent reply other threads:[~2020-06-12 18:47 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-10 17:29 [PATCH RFC v7 00/12] blk-mq/scsi: Provide hostwide shared tags for SCSI HBAs John Garry
2020-06-10 17:29 ` [PATCH RFC v7 01/12] blk-mq: rename BLK_MQ_F_TAG_SHARED as BLK_MQ_F_TAG_QUEUE_SHARED John Garry
2020-06-10 17:29 ` [PATCH RFC v7 02/12] blk-mq: rename blk_mq_update_tag_set_depth() John Garry
2020-06-11 2:57 ` Ming Lei
2020-06-11 8:26 ` John Garry
2020-06-23 11:25 ` John Garry
2020-06-23 14:23 ` Hannes Reinecke
2020-06-24 8:13 ` Kashyap Desai
2020-06-29 16:18 ` John Garry
2020-08-10 16:51 ` Kashyap Desai
2020-08-11 8:01 ` John Garry
2020-08-11 16:34 ` Kashyap Desai
2020-06-10 17:29 ` [PATCH RFC v7 03/12] blk-mq: Use pointers for blk_mq_tags bitmap tags John Garry
2020-06-10 17:29 ` [PATCH RFC v7 04/12] blk-mq: Facilitate a shared sbitmap per tagset John Garry
2020-06-11 3:37 ` Ming Lei
2020-06-11 10:09 ` John Garry
2020-06-10 17:29 ` [PATCH RFC v7 05/12] blk-mq: Record nr_active_requests per queue for when using shared sbitmap John Garry
2020-06-11 4:04 ` Ming Lei
2020-06-11 10:22 ` John Garry
2020-06-10 17:29 ` [PATCH RFC v7 06/12] blk-mq: Record active_queues_shared_sbitmap per tag_set " John Garry
2020-06-11 13:16 ` Hannes Reinecke
2020-06-11 14:22 ` John Garry
2020-06-10 17:29 ` [PATCH RFC v7 07/12] blk-mq: Add support in hctx_tags_bitmap_show() for a " John Garry
2020-06-11 13:19 ` Hannes Reinecke
2020-06-11 14:33 ` John Garry
2020-06-12 6:06 ` Hannes Reinecke
2020-06-29 15:32 ` About sbitmap_bitmap_show() and cleared bits (was Re: [PATCH RFC v7 07/12] blk-mq: Add support in hctx_tags_bitmap_show() for a shared sbitmap) John Garry
2020-06-30 6:33 ` Hannes Reinecke
2020-06-30 7:30 ` John Garry
2020-06-30 11:36 ` John Garry
2020-06-30 14:55 ` Bart Van Assche
2020-07-13 9:41 ` [PATCH RFC v7 07/12] blk-mq: Add support in hctx_tags_bitmap_show() for a shared sbitmap John Garry
2020-07-13 12:20 ` Hannes Reinecke
2020-06-10 17:29 ` [PATCH RFC v7 08/12] scsi: Add template flag 'host_tagset' John Garry
2020-06-10 17:29 ` [PATCH RFC v7 09/12] scsi: hisi_sas: Switch v3 hw to MQ John Garry
2020-06-10 17:29 ` [PATCH RFC v7 10/12] megaraid_sas: switch fusion adapters " John Garry
2020-07-02 10:23 ` Kashyap Desai
2020-07-06 8:23 ` John Garry
2020-07-06 8:45 ` Hannes Reinecke
2020-07-06 9:26 ` John Garry
2020-07-06 9:40 ` Hannes Reinecke
2020-07-06 19:19 ` Kashyap Desai
2020-07-07 7:58 ` John Garry
2020-07-07 14:45 ` Kashyap Desai
2020-07-07 16:17 ` John Garry
2020-07-09 19:01 ` Kashyap Desai
2020-07-10 8:10 ` John Garry
2020-07-13 7:55 ` Kashyap Desai
2020-07-13 8:42 ` John Garry
2020-07-19 19:07 ` Kashyap Desai
2020-07-20 7:23 ` Kashyap Desai
2020-07-20 9:18 ` John Garry
2020-07-21 1:13 ` Ming Lei
2020-07-21 6:53 ` Kashyap Desai
2020-07-22 4:12 ` Ming Lei
2020-07-22 5:30 ` Kashyap Desai
2020-07-22 8:04 ` Ming Lei
2020-07-22 9:32 ` John Garry
2020-07-23 14:07 ` Ming Lei
2020-07-23 17:29 ` John Garry
2020-07-24 2:47 ` Ming Lei
2020-07-28 7:54 ` John Garry
2020-07-28 8:45 ` Ming Lei
2020-07-29 5:25 ` Kashyap Desai
2020-07-29 15:36 ` Ming Lei
2020-07-29 18:31 ` Kashyap Desai
2020-08-04 8:36 ` Ming Lei
2020-08-04 9:27 ` Kashyap Desai
2020-08-05 8:40 ` Ming Lei
2020-08-06 10:25 ` Kashyap Desai
2020-08-06 13:38 ` Ming Lei
2020-08-06 14:37 ` Kashyap Desai
2020-08-06 15:29 ` Ming Lei
2020-08-08 19:05 ` Kashyap Desai
2020-08-09 2:16 ` Ming Lei
2020-08-10 16:38 ` Kashyap Desai
2020-08-11 8:09 ` John Garry
2020-08-04 17:00 ` John Garry
2020-08-05 2:56 ` Ming Lei
2020-07-28 8:01 ` Kashyap Desai
2020-07-08 11:31 ` John Garry
2020-06-10 17:29 ` [PATCH RFC v7 11/12] smartpqi: enable host tagset John Garry
2020-07-14 13:16 ` John Garry
2020-07-14 13:31 ` John Garry
2020-07-14 18:16 ` Don.Brace
2020-07-15 7:28 ` John Garry
2020-07-14 14:02 ` Hannes Reinecke
2020-08-18 8:33 ` John Garry
2020-06-10 17:29 ` [PATCH RFC v7 12/12] hpsa: enable host_tagset and switch to MQ John Garry
2020-07-14 7:37 ` John Garry
2020-07-14 7:41 ` Hannes Reinecke
2020-07-14 7:52 ` John Garry
2020-07-14 8:06 ` Ming Lei
2020-07-14 9:53 ` John Garry
2020-07-14 10:14 ` Ming Lei
2020-07-14 10:43 ` Hannes Reinecke
2020-07-14 10:19 ` Hannes Reinecke
2020-07-14 10:35 ` John Garry
2020-07-14 10:44 ` Ming Lei
2020-07-14 10:52 ` John Garry
2020-07-14 12:04 ` Ming Lei
2020-08-03 20:39 ` Don.Brace
2020-08-04 9:27 ` John Garry
2020-08-04 15:18 ` Don.Brace
2020-08-05 11:21 ` John Garry
2020-08-14 21:04 ` Don.Brace
2020-08-17 8:00 ` John Garry
2020-08-17 18:39 ` Don.Brace
2020-08-18 7:14 ` Hannes Reinecke
2020-07-16 16:14 ` Don.Brace
2020-07-16 19:45 ` Don.Brace
2020-07-17 10:11 ` John Garry
2020-06-11 3:07 ` [PATCH RFC v7 00/12] blk-mq/scsi: Provide hostwide shared tags for SCSI HBAs Ming Lei
2020-06-11 9:35 ` John Garry
2020-06-12 18:47 ` Kashyap Desai [this message]
2020-06-15 2:13 ` Ming Lei
2020-06-15 6:57 ` Kashyap Desai
2020-06-16 1:00 ` Ming Lei
2020-06-17 11:26 ` Kashyap Desai
2020-06-22 6:24 ` Hannes Reinecke
2020-06-23 0:55 ` Ming Lei
2020-06-23 11:50 ` Kashyap Desai
2020-06-23 12:11 ` Kashyap Desai
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=bbdec3b3fbeb9907d2ec66a2afa56c29@mail.gmail.com \
--to=kashyap.desai@broadcom.com \
--cc=axboe@kernel.dk \
--cc=bvanassche@acm.org \
--cc=chenxiang66@hisilicon.com \
--cc=don.brace@microsemi.com \
--cc=esc.storagedev@microsemi.com \
--cc=hare@suse.com \
--cc=hch@lst.de \
--cc=jejb@linux.ibm.com \
--cc=john.garry@huawei.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=martin.petersen@oracle.com \
--cc=megaraidlinux.pdl@broadcom.com \
--cc=ming.lei@redhat.com \
--cc=shivasharan.srikanteshwara@broadcom.com \
--cc=sumit.saxena@broadcom.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).