Commit 24d7071d authored by Tomas Henzl's avatar Tomas Henzl Committed by Martin K. Petersen
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scsi: mpi3mr: A performance fix 



Commit 0c52310f ("hrtimer: Ignore slack time for RT tasks in
schedule_hrtimeout_range()") effectivelly shortens a sleep in a polling
function in the driver.  That is causing a performance regression as the
new value of just 2us is too low, in certain tests the perf drop is ~30%.
Fix this by adjusting the sleep to 20us (close to the previous value).

Reported-by: default avatarJan Jurca <jjurca@redhat.com>
Signed-off-by: default avatarTomas Henzl <thenzl@redhat.com>
Acked-by: default avatarSumit Saxena <sumit.saxena@broadcom.com>
Link: https://lore.kernel.org/r/20240903144729.37218-1-thenzl@redhat.com


Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 0c40f079

drivers/scsi/mpi3mr/mpi3mr.h

+1 −1
Original line number Diff line number Diff line
@@ -178,7 +178,7 @@ extern atomic64_t event_counter; 
#define MPI3MR_DEFAULT_SDEV_QD	32



/* Definitions for Threaded IRQ poll*/

#define MPI3MR_IRQ_POLL_SLEEP			2

#define MPI3MR_IRQ_POLL_SLEEP			20

#define MPI3MR_IRQ_POLL_TRIGGER_IOCOUNT		8



/* Definitions for the controller security status*/

drivers/scsi/mpi3mr/mpi3mr_fw.c

+1 −1
Original line number Diff line number Diff line
@@ -728,7 +728,7 @@ static irqreturn_t mpi3mr_isr_poll(int irq, void *privdata) 
			    mpi3mr_process_op_reply_q(mrioc,

				intr_info->op_reply_q);



		usleep_range(MPI3MR_IRQ_POLL_SLEEP, 10 * MPI3MR_IRQ_POLL_SLEEP);

		usleep_range(MPI3MR_IRQ_POLL_SLEEP, MPI3MR_IRQ_POLL_SLEEP + 1);



	} while (atomic_read(&intr_info->op_reply_q->pend_ios) &&

	    (num_op_reply < mrioc->max_host_ios));