diff options
| author | Dick Kennedy <dick.kennedy@broadcom.com> | 2020-06-30 14:49:59 -0700 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2020-07-02 23:06:42 -0400 |
| commit | 317aeb83c92b26f8c6a3e318157f20892556c343 (patch) | |
| tree | f8afe5c73764db2838b6930b8102e4f21fd487d4 /drivers/scsi/lpfc/lpfc.h | |
| parent | f0020e428af7c7a705a264be21a67b1c89574af0 (diff) | |
| download | lwn-317aeb83c92b26f8c6a3e318157f20892556c343.tar.gz lwn-317aeb83c92b26f8c6a3e318157f20892556c343.zip | |
scsi: lpfc: Add blk_io_poll support for latency improvment
Although the existing implementation is very good at high I/O load, on
tests involving light load, especially on only a few hardware queues,
latency was a little higher than it can be due to using workqueue
scheduling. Other tasks in the system can delay handling.
Change the lower level to use irq_poll by default which uses a softirq for
I/O completion. This gives better latency as variance in when the cq is
processed is reduced over the workqueue interface. However, as high load is
better served by not being in softirq when the CPU is loaded, work queues
are still used under high I/O load.
Link: https://lore.kernel.org/r/20200630215001.70793-13-jsmart2021@gmail.com
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/lpfc/lpfc.h')
| -rw-r--r-- | drivers/scsi/lpfc/lpfc.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/scsi/lpfc/lpfc.h b/drivers/scsi/lpfc/lpfc.h index c3ceb6e5b061..2ddcdedfdb8c 100644 --- a/drivers/scsi/lpfc/lpfc.h +++ b/drivers/scsi/lpfc/lpfc.h @@ -709,6 +709,9 @@ struct lpfc_hba { struct workqueue_struct *wq; struct delayed_work eq_delay_work; +#define LPFC_IDLE_STAT_DELAY 1000 + struct delayed_work idle_stat_delay_work; + struct lpfc_sli sli; uint8_t pci_dev_grp; /* lpfc PCI dev group: 0x0, 0x1, 0x2,... */ uint32_t sli_rev; /* SLI2, SLI3, or SLI4 */ |