RE: [PATCH RFT 0/3] blk-mq: Optimise blk_mq_queue_tag_busy_iter() for shared tags

Kashyap Desai
2021-11-25T13:54:48Z

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> -----Original Message-----
> From: Kashyap Desai [mailto:kashyap.desai@broadcom.com]
> Sent: Monday, November 15, 2021 10:02 PM
> To: 'John Garry' <john.garry@huawei.com>; 'axboe@kernel.dk'
> <axboe@kernel.dk>
> Cc: 'linux-block@vger.kernel.org' <linux-block@vger.kernel.org>; 'linux-
> kernel@vger.kernel.org' <linux-kernel@vger.kernel.org>;
> 'ming.lei@redhat.com'
> <ming.lei@redhat.com>; 'hare@suse.de' <hare@suse.de>
> Subject: RE: [PATCH RFT 0/3] blk-mq: Optimise blk_mq_queue_tag_busy_iter()
> for shared tags
>
> > Hi Kashyap,
> >
> > Any chance you can try this series or give an update on the issue
> > reported earlier?
>
> John -
>
> I will try something this week and let you know.

John - I tested patchset and looks good. Issue reported at below thread is
fixed.
https://lore.kernel.org/linux-block/e4e92abbe9d52bcba6b8cc6c91c442cc@mail.gmail.com/

Here is perf top data.

5.70% [megaraid_sas] [k] complete_cmd_fusion
3.80% [megaraid_sas] [k]
megasas_build_and_issue_cmd_fusion
2.75% [kernel] [k] syscall_return_via_sysret
2.68% [kernel] [k] entry_SYSCALL_64
2.22% [kernel] [k] io_submit_one
2.19% [megaraid_sas] [k] megasas_build_ldio_fusion
1.95% [kernel] [k] llist_add_batch
1.80% [kernel] [k] llist_reverse_order
1.79% [kernel] [k] scsi_complete
1.73% [kernel] [k] scsi_queue_rq
1.66% [kernel] [k] check_preemption_disabled
1.37% [megaraid_sas] [k] megasas_queue_command
1.16% [kernel] [k] native_irq_return_iret
1.11% [kernel] [k] aio_complete_rw
1.07% [kernel] [k] read_tsc
1.06% fio [.] __fio_gettime
1.05% [kernel] [k] flush_smp_call_function_queue
1.03% [kernel] [k] blk_complete_reqs
1.00% [kernel] [k] blk_mq_free_request
0.98% [kernel] [k] sbitmap_get

I will continue testing and let you know how it goes.

Kashyap

>
> >
> > thanks @ Ming for the reviews.
> >
> > Cheers,
> > John
> >

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