scsi: lpfc: Add auto EQ delay logic

Administrator intervention is currently required to get good numbers
when switching from running latency tests to IOPS tests.

The configured interrupt coalescing values will greatly effect the
results of these tests.  Currently, the driver has a single coalescing
value set by values of the module attribute.  This patch changes the
driver to support auto-configuration of the coalescing value based on
the total number of outstanding IOs and average number of CQEs processed
per interrupt for an EQ.  Values are checked every 5 seconds.

The driver defaults to the automatic selection. Automatic selection can
be disabled by the new lpfc_auto_imax module_parameter.

Older hardware can only change interrupt coalescing by mailbox
command. Newer hardware supports change via a register. The patch
support both.

Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 19 insertions, 1 deletions

diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
index 8eee39de15f7..66269e342c7e 100644
--- a/drivers/scsi/lpfc/lpfc_attr.c
+++ b/drivers/scsi/lpfc/lpfc_attr.c
@@ -4481,9 +4481,11 @@ lpfc_fcp_imax_store(struct device *dev, struct device_attribute *attr,
 		return -EINVAL;
 
 	phba->cfg_fcp_imax = (uint32_t)val;
+	phba->initial_imax = phba->cfg_fcp_imax;
 
 	for (i = 0; i < phba->io_channel_irqs; i += LPFC_MAX_EQ_DELAY_EQID_CNT)
-		lpfc_modify_hba_eq_delay(phba, i);
+		lpfc_modify_hba_eq_delay(phba, i, LPFC_MAX_EQ_DELAY_EQID_CNT,
+					 val);
 
 	return strlen(buf);
 }
@@ -4538,6 +4540,16 @@ lpfc_fcp_imax_init(struct lpfc_hba *phba, int val)
 static DEVICE_ATTR(lpfc_fcp_imax, S_IRUGO | S_IWUSR,
 		   lpfc_fcp_imax_show, lpfc_fcp_imax_store);
 
+/*
+ * lpfc_auto_imax: Controls Auto-interrupt coalescing values support.
+ *       0       No auto_imax support
+ *       1       auto imax on
+ * Auto imax will change the value of fcp_imax on a per EQ basis, using
+ * the EQ Delay Multiplier, depending on the activity for that EQ.
+ * Value range [0,1]. Default value is 1.
+ */
+LPFC_ATTR_RW(auto_imax, 1, 0, 1, "Enable Auto imax");
+
 /**
  * lpfc_state_show - Display current driver CPU affinity
  * @dev: class converted to a Scsi_host structure.
@@ -5164,6 +5176,7 @@ struct device_attribute *lpfc_hba_attrs[] = {
 	&dev_attr_lpfc_task_mgmt_tmo,
 	&dev_attr_lpfc_use_msi,
 	&dev_attr_lpfc_nvme_oas,
+	&dev_attr_lpfc_auto_imax,
 	&dev_attr_lpfc_fcp_imax,
 	&dev_attr_lpfc_fcp_cpu_map,
 	&dev_attr_lpfc_fcp_io_channel,
@@ -6182,6 +6195,7 @@ lpfc_get_cfgparam(struct lpfc_hba *phba)
 	lpfc_enable_SmartSAN_init(phba, lpfc_enable_SmartSAN);
 	lpfc_use_msi_init(phba, lpfc_use_msi);
 	lpfc_nvme_oas_init(phba, lpfc_nvme_oas);
+	lpfc_auto_imax_init(phba, lpfc_auto_imax);
 	lpfc_fcp_imax_init(phba, lpfc_fcp_imax);
 	lpfc_fcp_cpu_map_init(phba, lpfc_fcp_cpu_map);
 	lpfc_enable_hba_reset_init(phba, lpfc_enable_hba_reset);
@@ -6226,6 +6240,10 @@ lpfc_get_cfgparam(struct lpfc_hba *phba)
 			phba->cfg_enable_fc4_type |= LPFC_ENABLE_FCP;
 	}
 
+	if (phba->cfg_auto_imax && !phba->cfg_fcp_imax)
+		phba->cfg_auto_imax = 0;
+	phba->initial_imax = phba->cfg_fcp_imax;
+
 	/* A value of 0 means use the number of CPUs found in the system */
 	if (phba->cfg_fcp_io_channel == 0)
 		phba->cfg_fcp_io_channel = phba->sli4_hba.num_present_cpu;