From: Sumit Saxena <sumit.saxena@broadcom.com>
To: John Garry <john.garry@huawei.com>
Cc: Hannes Reinecke <hare@suse.de>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Jens Axboe <axboe@kernel.dk>, Christoph Hellwig <hch@lst.de>,
James Bottomley <james.bottomley@hansenpartnership.com>,
Ming Lei <ming.lei@redhat.com>,
Linux SCSI List <linux-scsi@vger.kernel.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
Hannes Reinecke <hare@suse.com>
Subject: Re: [PATCH 09/11] megaraid_sas: switch fusion adapters to MQ
Date: Mon, 17 Feb 2020 15:39:45 +0530 [thread overview]
Message-ID: <CAL2rwxooozyNvx30Qsr+15XmuYJ4VUyXBHNz3-iXVqQZabATJQ@mail.gmail.com> (raw)
In-Reply-To: <ab0397bf-19a0-41b1-3bd6-a08dbdd94cdb@huawei.com>
On Thu, Feb 13, 2020 at 3:37 PM John Garry <john.garry@huawei.com> wrote:
>
> On 17/01/2020 11:18, Sumit Saxena wrote:
> >>>> or doing a performance test here.
> >>> Hi Hannes,
> >>>
>
> Hi Sumit,
>
> >>> Sorry for the delay in replying, I observed a few issues with this patchset:
> >>>
> >>> 1. "blk_mq_unique_tag_to_hwq(tag)" does not return MSI-x vector to
> >>> which IO submitter CPU is affined with. Due to this IO submission and
> >>> completion CPUs are different which causes performance drop for low
> >>> latency workloads.
> >> Hi Sumit,
> >>
> >> So the new code has:
> >>
> >> megasas_build_ldio_fusion()
> >> {
> >>
> >> cmd->request_desc->SCSIIO.MSIxIndex =
> >> blk_mq_unique_tag_to_hwq(tag);
> >>
> >> }
> >>
> >> So the value here is hw queue index from blk-mq point of view, and not
> >> megaraid_sas msix index, as you alluded to.
> > Yes John, value filled in "cmd->request_desc->SCSIIO.MSIxIndex" is HW
> > queue index.
> >
> >> So we get 80 msix, 8 are reserved for low_latency_index_start (that's
> >> how it seems to me), and we report other 72 as #hw queues = 72 to SCSI
> >> midlayer.
> >>
> >> So I think that this should be:
> >>
> >> cmd->request_desc->SCSIIO.MSIxIndex =
> >> blk_mq_unique_tag_to_hwq(tag) + low_latency_index_start;
>
> Can you possibly test performance again with this local change, or would
> you rather an updated patchset be sent?
Updated patchset is not required. I will do performance run with this
change and update.
Thanks,
Sumit
>
> > Agreed, this should return correct HW queue index.
> >>
>
>
> Thanks,
> John
next prev parent reply other threads:[~2020-02-17 10:10 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-02 15:39 [PATCH RFC v5 00/11] blk-mq/scsi: Provide hostwide shared tags for SCSI HBAs Hannes Reinecke
2019-12-02 15:39 ` [PATCH 01/11] blk-mq: Remove some unused function arguments Hannes Reinecke
2019-12-02 15:39 ` [PATCH 02/11] blk-mq: rename BLK_MQ_F_TAG_SHARED as BLK_MQ_F_TAG_QUEUE_SHARED Hannes Reinecke
2019-12-02 15:39 ` [PATCH 03/11] blk-mq: rename blk_mq_update_tag_set_depth() Hannes Reinecke
2019-12-03 14:30 ` John Garry
2019-12-03 14:53 ` Hannes Reinecke
2019-12-02 15:39 ` [PATCH 04/11] blk-mq: Facilitate a shared sbitmap per tagset Hannes Reinecke
2019-12-03 14:54 ` John Garry
2019-12-03 15:02 ` Hannes Reinecke
2019-12-04 10:24 ` John Garry
2019-12-03 16:38 ` Bart Van Assche
2019-12-02 15:39 ` [PATCH 05/11] blk-mq: add WARN_ON in blk_mq_free_rqs() Hannes Reinecke
2019-12-02 15:39 ` [PATCH 06/11] blk-mq: move shared sbitmap into elevator queue Hannes Reinecke
2019-12-02 15:39 ` [PATCH 07/11] scsi: Add template flag 'host_tagset' Hannes Reinecke
2019-12-02 15:39 ` [PATCH 08/11] scsi: hisi_sas: Switch v3 hw to MQ Hannes Reinecke
2019-12-02 15:39 ` [PATCH 09/11] megaraid_sas: switch fusion adapters " Hannes Reinecke
2019-12-09 10:10 ` Sumit Saxena
2019-12-09 11:02 ` Hannes Reinecke
2020-01-10 4:00 ` Sumit Saxena
2020-01-10 12:18 ` John Garry
2020-01-13 17:42 ` John Garry
2020-01-14 7:05 ` Hannes Reinecke
2020-01-16 15:47 ` John Garry
2020-01-16 17:45 ` Hannes Reinecke
2020-01-17 11:40 ` Sumit Saxena
2020-01-17 11:18 ` Sumit Saxena
2020-02-13 10:07 ` John Garry
2020-02-17 10:09 ` Sumit Saxena [this message]
2020-01-09 11:55 ` John Garry
2020-01-09 15:19 ` Hannes Reinecke
2020-01-09 18:17 ` John Garry
2020-01-10 2:00 ` Ming Lei
2020-01-10 12:09 ` John Garry
2020-01-14 13:57 ` John Garry
2019-12-02 15:39 ` [PATCH 10/11] smartpqi: enable host tagset Hannes Reinecke
2019-12-02 15:39 ` [PATCH 11/11] hpsa: enable host_tagset and switch to MQ Hannes Reinecke
2020-02-26 11:09 ` [PATCH RFC v5 00/11] blk-mq/scsi: Provide hostwide shared tags for SCSI HBAs John Garry
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=CAL2rwxooozyNvx30Qsr+15XmuYJ4VUyXBHNz3-iXVqQZabATJQ@mail.gmail.com \
--to=sumit.saxena@broadcom.com \
--cc=axboe@kernel.dk \
--cc=hare@suse.com \
--cc=hare@suse.de \
--cc=hch@lst.de \
--cc=james.bottomley@hansenpartnership.com \
--cc=john.garry@huawei.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=martin.petersen@oracle.com \
--cc=ming.lei@redhat.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).