From: Hannes Reinecke <hare@suse.de>
To: Sumit Saxena <sumit.saxena@broadcom.com>,
"Martin K . Petersen" <martin.petersen@oracle.com>,
Jens Axboe <axboe@kernel.dk>
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John Garry <john.g.garry@oracle.com>
Subject: Re: [PATCH v3 4/4] scsi: use percpu counters for iostat counters in struct scsi_device
Date: Wed, 10 Jun 2026 08:21:07 +0200 [thread overview]
Message-ID: <ca44e52a-ddf7-4bf8-9634-5afaf7413176@suse.de> (raw)
In-Reply-To: <20260609121806.2121755-5-sumit.saxena@broadcom.com>
On 6/9/26 14:18, Sumit Saxena wrote:
> iorequest_cnt and iodone_cnt are updated on every command dispatch and
> completion, often from different CPUs on high queue depth workloads.
> Using adjacent atomic_t fields causes cache line contention between the
> submission and completion paths.
>
> Extend the same treatment to ioerr_cnt and iotmo_cnt so all four iostat
> counters in struct scsi_device use struct percpu_counter.
>
> Suggested-by: John Garry <john.g.garry@oracle.com>
> Signed-off-by: Sumit Saxena <sumit.saxena@broadcom.com>
> ---
> drivers/scsi/scsi_error.c | 4 ++--
> drivers/scsi/scsi_lib.c | 10 +++++-----
> drivers/scsi/scsi_scan.c | 8 ++++++++
> drivers/scsi/scsi_sysfs.c | 23 ++++++++++++++---------
> drivers/scsi/sd.c | 2 +-
> include/scsi/scsi_device.h | 9 +++++----
> 6 files changed, 35 insertions(+), 21 deletions(-)
>
Good idea.
Reviewed-by: Hannes Reinecke <hare@kernel.org>
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@suse.de +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich
prev parent reply other threads:[~2026-06-10 6:21 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-09 12:17 [PATCH v3 0/4] scsi/block: NUMA-local scan allocations, shared-tag path cleanup, and SCSI I/O counters Sumit Saxena
2026-06-09 12:18 ` [PATCH v3 1/4] scsi: scan: allocate sdev and starget on the NUMA node of the host adapter Sumit Saxena
2026-06-10 6:00 ` Hannes Reinecke
2026-06-09 12:18 ` [PATCH v3 2/4] scsi: host: allocate struct Scsi_Host " Sumit Saxena
2026-06-09 13:03 ` John Garry
2026-06-10 5:59 ` Hannes Reinecke
2026-06-09 12:18 ` [PATCH v3 3/4] block: drop shared-tag fairness throttling Sumit Saxena
2026-06-10 6:14 ` Christoph Hellwig
[not found] ` <CAL2rwxr1uGshb1o=jvP2OnBffNz2cKXj8tHuAUCN5HFuy2vB_g@mail.gmail.com>
2026-06-10 16:35 ` Keith Busch
2026-06-10 6:18 ` Hannes Reinecke
2026-06-09 12:18 ` [PATCH v3 4/4] scsi: use percpu counters for iostat counters in struct scsi_device Sumit Saxena
2026-06-10 6:21 ` Hannes Reinecke [this message]
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