diff options
| author | Dick Kennedy <dick.kennedy@broadcom.com> | 2020-07-01 00:49:59 +0300 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2020-07-03 06:06:42 +0300 |
| commit | 317aeb83c92b26f8c6a3e318157f20892556c343 (patch) | |
| tree | f8afe5c73764db2838b6930b8102e4f21fd487d4 /drivers/scsi/lpfc/lpfc_sli4.h | |
| parent | f0020e428af7c7a705a264be21a67b1c89574af0 (diff) | |
| download | linux-317aeb83c92b26f8c6a3e318157f20892556c343.tar.xz | |
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_sli4.h')
| -rw-r--r-- | drivers/scsi/lpfc/lpfc_sli4.h | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/scsi/lpfc/lpfc_sli4.h b/drivers/scsi/lpfc/lpfc_sli4.h index 4decb53d81c3..a966cdeb52ee 100644 --- a/drivers/scsi/lpfc/lpfc_sli4.h +++ b/drivers/scsi/lpfc/lpfc_sli4.h @@ -20,6 +20,9 @@ * included with this package. * *******************************************************************/ +#include <linux/irq_poll.h> +#include <linux/cpufreq.h> + #if defined(CONFIG_DEBUG_FS) && !defined(CONFIG_SCSI_LPFC_DEBUG_FS) #define CONFIG_SCSI_LPFC_DEBUG_FS #endif @@ -135,6 +138,16 @@ struct lpfc_rqb { struct rqb_dmabuf *); }; +enum lpfc_poll_mode { + LPFC_QUEUE_WORK, + LPFC_IRQ_POLL +}; + +struct lpfc_idle_stat { + u64 prev_idle; + u64 prev_wall; +}; + struct lpfc_queue { struct list_head list; struct list_head wq_list; @@ -265,6 +278,10 @@ struct lpfc_queue { struct lpfc_queue *assoc_qp; struct list_head _poll_list; void **q_pgs; /* array to index entries per page */ + +#define LPFC_IRQ_POLL_WEIGHT 256 + struct irq_poll iop; + enum lpfc_poll_mode poll_mode; }; struct lpfc_sli4_link { @@ -926,6 +943,7 @@ struct lpfc_sli4_hba { #ifdef CONFIG_SCSI_LPFC_DEBUG_FS struct lpfc_hdwq_stat __percpu *c_stat; #endif + struct lpfc_idle_stat *idle_stat; uint32_t conf_trunk; #define lpfc_conf_trunk_port0_WORD conf_trunk #define lpfc_conf_trunk_port0_SHIFT 0 |