scsi: lpfc: Make ktime sampling more accurate

Need to make ktime samples more accurate

If ktime is turned on in the middle of an IO, the max calculation could
be misleading. Base sampling on the start time of the IO as opposed to
ktime_on.

Make ISR ktime timestamps be from when CQE is read instead of EQE.
Added additional sanity checks when deciding whether to accept an IO
sample or not.
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/lpfc/lpfc_nvme.c

@@ -667,15 +667,17 @@ lpfc_nvme_ktime(struct lpfc_hba *phba,
 		struct lpfc_nvme_buf *lpfc_ncmd)
 {
 	uint64_t seg1, seg2, seg3, seg4;
+	uint64_t segsum;
 
-	if (!phba->ktime_on)
-		return;
 	if (!lpfc_ncmd->ts_last_cmd ||
 	    !lpfc_ncmd->ts_cmd_start ||
 	    !lpfc_ncmd->ts_cmd_wqput ||
 	    !lpfc_ncmd->ts_isr_cmpl ||
 	    !lpfc_ncmd->ts_data_nvme)
 		return;
+
+	if (lpfc_ncmd->ts_data_nvme < lpfc_ncmd->ts_cmd_start)
+		return;
 	if (lpfc_ncmd->ts_cmd_start < lpfc_ncmd->ts_last_cmd)
 		return;
 	if (lpfc_ncmd->ts_cmd_wqput < lpfc_ncmd->ts_cmd_start)
@@ -695,15 +697,23 @@ lpfc_nvme_ktime(struct lpfc_hba *phba,
 	 * cmpl is handled off to the NVME Layer.
 	 */
 	seg1 = lpfc_ncmd->ts_cmd_start - lpfc_ncmd->ts_last_cmd;
-	if (seg1 > 5000000)  /* 5 ms - for sequential IOs */
-		return;
+	if (seg1 > 5000000)  /* 5 ms - for sequential IOs only */
+		seg1 = 0;
 
 	/* Calculate times relative to start of IO */
 	seg2 = (lpfc_ncmd->ts_cmd_wqput - lpfc_ncmd->ts_cmd_start);
-	seg3 = (lpfc_ncmd->ts_isr_cmpl -
-		lpfc_ncmd->ts_cmd_start) - seg2;
-	seg4 = (lpfc_ncmd->ts_data_nvme -
-		lpfc_ncmd->ts_cmd_start) - seg2 - seg3;
+	segsum = seg2;
+	seg3 = lpfc_ncmd->ts_isr_cmpl - lpfc_ncmd->ts_cmd_start;
+	if (segsum > seg3)
+		return;
+	seg3 -= segsum;
+	segsum += seg3;
+
+	seg4 = lpfc_ncmd->ts_data_nvme - lpfc_ncmd->ts_cmd_start;
+	if (segsum > seg4)
+		return;
+	seg4 -= segsum;
+
 	phba->ktime_data_samples++;
 	phba->ktime_seg1_total += seg1;
 	if (seg1 < phba->ktime_seg1_min)
@@ -902,7 +912,7 @@ lpfc_nvme_io_cmd_wqe_cmpl(struct lpfc_hba *phba, struct lpfc_iocbq *pwqeIn,
 	 * owns the dma address.
 	 */
 #ifdef CONFIG_SCSI_LPFC_DEBUG_FS
-	if (phba->ktime_on) {
+	if (lpfc_ncmd->ts_cmd_start) {
 		lpfc_ncmd->ts_isr_cmpl = pwqeIn->isr_timestamp;
 		lpfc_ncmd->ts_data_nvme = ktime_get_ns();
 		phba->ktime_last_cmd = lpfc_ncmd->ts_data_nvme;
@@ -1283,9 +1293,11 @@ lpfc_nvme_fcp_io_submit(struct nvme_fc_local_port *pnvme_lport,
 		goto out_fail;
 	}
 #ifdef CONFIG_SCSI_LPFC_DEBUG_FS
-	if (phba->ktime_on) {
+	if (start) {
 		lpfc_ncmd->ts_cmd_start = start;
 		lpfc_ncmd->ts_last_cmd = phba->ktime_last_cmd;
+	} else {
+		lpfc_ncmd->ts_cmd_start = 0;
 	}
 #endif
 
@@ -1336,7 +1348,7 @@ lpfc_nvme_fcp_io_submit(struct nvme_fc_local_port *pnvme_lport,
 	}
 
 #ifdef CONFIG_SCSI_LPFC_DEBUG_FS
-	if (phba->ktime_on)
+	if (lpfc_ncmd->ts_cmd_start)
 		lpfc_ncmd->ts_cmd_wqput = ktime_get_ns();
 
 	if (phba->cpucheck_on & LPFC_CHECK_NVME_IO) {

drivers/scsi/lpfc/lpfc_nvmet.c

@@ -221,9 +221,8 @@ lpfc_nvmet_ctxbuf_post(struct lpfc_hba *phba, struct lpfc_nvmet_ctxbuf *ctx_buf)
 		spin_lock_init(&ctxp->ctxlock);
 
 #ifdef CONFIG_SCSI_LPFC_DEBUG_FS
-		if (phba->ktime_on) {
+		if (ctxp->ts_cmd_nvme) {
 			ctxp->ts_cmd_nvme = ktime_get_ns();
-			ctxp->ts_isr_cmd = ctxp->ts_cmd_nvme;
 			ctxp->ts_nvme_data = 0;
 			ctxp->ts_data_wqput = 0;
 			ctxp->ts_isr_data = 0;
@@ -289,9 +288,7 @@ lpfc_nvmet_ktime(struct lpfc_hba *phba,
 {
 	uint64_t seg1, seg2, seg3, seg4, seg5;
 	uint64_t seg6, seg7, seg8, seg9, seg10;
-
-	if (!phba->ktime_on)
-		return;
+	uint64_t segsum;
 
 	if (!ctxp->ts_isr_cmd || !ctxp->ts_cmd_nvme ||
 	    !ctxp->ts_nvme_data || !ctxp->ts_data_wqput ||
@@ -300,6 +297,8 @@ lpfc_nvmet_ktime(struct lpfc_hba *phba,
 	    !ctxp->ts_isr_status || !ctxp->ts_status_nvme)
 		return;
 
+	if (ctxp->ts_status_nvme < ctxp->ts_isr_cmd)
+		return;
 	if (ctxp->ts_isr_cmd  > ctxp->ts_cmd_nvme)
 		return;
 	if (ctxp->ts_cmd_nvme > ctxp->ts_nvme_data)
@@ -344,34 +343,66 @@ lpfc_nvmet_ktime(struct lpfc_hba *phba,
 	 * (Segments 1 thru 4) for READDATA_RSP
 	 */
 	seg1 = ctxp->ts_cmd_nvme - ctxp->ts_isr_cmd;
-	seg2 = (ctxp->ts_nvme_data - ctxp->ts_isr_cmd) - seg1;
-	seg3 = (ctxp->ts_data_wqput - ctxp->ts_isr_cmd) -
-		seg1 - seg2;
-	seg4 = (ctxp->ts_isr_data - ctxp->ts_isr_cmd) -
-		seg1 - seg2 - seg3;
-	seg5 = (ctxp->ts_data_nvme - ctxp->ts_isr_cmd) -
-		seg1 - seg2 - seg3 - seg4;
+	segsum = seg1;
+
+	seg2 = ctxp->ts_nvme_data - ctxp->ts_isr_cmd;
+	if (segsum > seg2)
+		return;
+	seg2 -= segsum;
+	segsum += seg2;
+
+	seg3 = ctxp->ts_data_wqput - ctxp->ts_isr_cmd;
+	if (segsum > seg3)
+		return;
+	seg3 -= segsum;
+	segsum += seg3;
+
+	seg4 = ctxp->ts_isr_data - ctxp->ts_isr_cmd;
+	if (segsum > seg4)
+		return;
+	seg4 -= segsum;
+	segsum += seg4;
+
+	seg5 = ctxp->ts_data_nvme - ctxp->ts_isr_cmd;
+	if (segsum > seg5)
+		return;
+	seg5 -= segsum;
+	segsum += seg5;
+
 
 	/* For auto rsp commands seg6 thru seg10 will be 0 */
 	if (ctxp->ts_nvme_status > ctxp->ts_data_nvme) {
-		seg6 = (ctxp->ts_nvme_status -
-			ctxp->ts_isr_cmd) -
-			seg1 - seg2 - seg3 - seg4 - seg5;
-		seg7 = (ctxp->ts_status_wqput -
-			ctxp->ts_isr_cmd) -
-			seg1 - seg2 - seg3 -
-			seg4 - seg5 - seg6;
-		seg8 = (ctxp->ts_isr_status -
-			ctxp->ts_isr_cmd) -
-			seg1 - seg2 - seg3 - seg4 -
-			seg5 - seg6 - seg7;
-		seg9 = (ctxp->ts_status_nvme -
-			ctxp->ts_isr_cmd) -
-			seg1 - seg2 - seg3 - seg4 -
-			seg5 - seg6 - seg7 - seg8;
+		seg6 = ctxp->ts_nvme_status - ctxp->ts_isr_cmd;
+		if (segsum > seg6)
+			return;
+		seg6 -= segsum;
+		segsum += seg6;
+
+		seg7 = ctxp->ts_status_wqput - ctxp->ts_isr_cmd;
+		if (segsum > seg7)
+			return;
+		seg7 -= segsum;
+		segsum += seg7;
+
+		seg8 = ctxp->ts_isr_status - ctxp->ts_isr_cmd;
+		if (segsum > seg8)
+			return;
+		seg8 -= segsum;
+		segsum += seg8;
+
+		seg9 = ctxp->ts_status_nvme - ctxp->ts_isr_cmd;
+		if (segsum > seg9)
+			return;
+		seg9 -= segsum;
+		segsum += seg9;
+
+		if (ctxp->ts_isr_status < ctxp->ts_isr_cmd)
+			return;
 		seg10 = (ctxp->ts_isr_status -
 			ctxp->ts_isr_cmd);
 	} else {
+		if (ctxp->ts_isr_data < ctxp->ts_isr_cmd)
+			return;
 		seg6 =  0;
 		seg7 =  0;
 		seg8 =  0;
@@ -519,7 +550,7 @@ lpfc_nvmet_xmt_fcp_op_cmp(struct lpfc_hba *phba, struct lpfc_iocbq *cmdwqe,
 		ctxp->entry_cnt++;
 
 #ifdef CONFIG_SCSI_LPFC_DEBUG_FS
-		if (phba->ktime_on) {
+		if (ctxp->ts_cmd_nvme) {
 			if (rsp->op == NVMET_FCOP_READDATA_RSP) {
 				ctxp->ts_isr_data =
 					cmdwqe->isr_timestamp;
@@ -553,7 +584,7 @@ lpfc_nvmet_xmt_fcp_op_cmp(struct lpfc_hba *phba, struct lpfc_iocbq *cmdwqe,
 #endif
 		rsp->done(rsp);
 #ifdef CONFIG_SCSI_LPFC_DEBUG_FS
-		if (phba->ktime_on)
+		if (ctxp->ts_cmd_nvme)
 			lpfc_nvmet_ktime(phba, ctxp);
 #endif
 		/* lpfc_nvmet_xmt_fcp_release() will recycle the context */
@@ -563,7 +594,7 @@ lpfc_nvmet_xmt_fcp_op_cmp(struct lpfc_hba *phba, struct lpfc_iocbq *cmdwqe,
 		memset(((char *)cmdwqe) + start_clean, 0,
 		       (sizeof(struct lpfc_iocbq) - start_clean));
 #ifdef CONFIG_SCSI_LPFC_DEBUG_FS
-		if (phba->ktime_on) {
+		if (ctxp->ts_cmd_nvme) {
 			ctxp->ts_isr_data = cmdwqe->isr_timestamp;
 			ctxp->ts_data_nvme = ktime_get_ns();
 		}
@@ -679,7 +710,7 @@ lpfc_nvmet_xmt_fcp_op(struct nvmet_fc_target_port *tgtport,
 	int rc;
 
 #ifdef CONFIG_SCSI_LPFC_DEBUG_FS
-	if (phba->ktime_on) {
+	if (ctxp->ts_cmd_nvme) {
 		if (rsp->op == NVMET_FCOP_RSP)
 			ctxp->ts_nvme_status = ktime_get_ns();
 		else
@@ -734,7 +765,7 @@ lpfc_nvmet_xmt_fcp_op(struct nvmet_fc_target_port *tgtport,
 	rc = lpfc_sli4_issue_wqe(phba, LPFC_FCP_RING, nvmewqeq);
 	if (rc == WQE_SUCCESS) {
 #ifdef CONFIG_SCSI_LPFC_DEBUG_FS
-		if (!phba->ktime_on)
+		if (!ctxp->ts_cmd_nvme)
 			return 0;
 		if (rsp->op == NVMET_FCOP_RSP)
 			ctxp->ts_status_wqput = ktime_get_ns();
@@ -1633,7 +1664,7 @@ lpfc_nvmet_unsol_fcp_buffer(struct lpfc_hba *phba,
 	spin_lock_init(&ctxp->ctxlock);
 
 #ifdef CONFIG_SCSI_LPFC_DEBUG_FS
-	if (phba->ktime_on) {
+	if (isr_timestamp) {
 		ctxp->ts_isr_cmd = isr_timestamp;
 		ctxp->ts_cmd_nvme = ktime_get_ns();
 		ctxp->ts_nvme_data = 0;
@@ -1644,6 +1675,8 @@ lpfc_nvmet_unsol_fcp_buffer(struct lpfc_hba *phba,
 		ctxp->ts_status_wqput = 0;
 		ctxp->ts_isr_status = 0;
 		ctxp->ts_status_nvme = 0;
+	} else {
+		ctxp->ts_cmd_nvme = 0;
 	}
 #endif
 

drivers/scsi/lpfc/lpfc_sli.c

@@ -13064,13 +13064,20 @@ lpfc_sli4_sp_handle_eqe(struct lpfc_hba *phba, struct lpfc_eqe *eqe,
 		break;
 	case LPFC_WCQ:
 		while ((cqe = lpfc_sli4_cq_get(cq))) {
-			if ((cq->subtype == LPFC_FCP) ||
-			    (cq->subtype == LPFC_NVME))
+			if (cq->subtype == LPFC_FCP ||
+			    cq->subtype == LPFC_NVME) {
+#ifdef CONFIG_SCSI_LPFC_DEBUG_FS
+				if (phba->ktime_on)
+					cq->isr_timestamp = ktime_get_ns();
+				else
+					cq->isr_timestamp = 0;
+#endif
 				workposted |= lpfc_sli4_fp_handle_cqe(phba, cq,
 								       cqe);
-			else
+			} else {
 				workposted |= lpfc_sli4_sp_handle_cqe(phba, cq,
 								      cqe);
+			}
 			if (!(++ecount % cq->entry_repost))
 				break;
 		}
@@ -13155,11 +13162,9 @@ lpfc_sli4_fp_handle_fcp_wcqe(struct lpfc_hba *phba, struct lpfc_queue *cq,
 				bf_get(lpfc_wcqe_c_request_tag, wcqe));
 		return;
 	}
-
-	if (cq->assoc_qp)
-		cmdiocbq->isr_timestamp =
-			cq->assoc_qp->isr_timestamp;
-
+#ifdef CONFIG_SCSI_LPFC_DEBUG_FS
+	cmdiocbq->isr_timestamp = cq->isr_timestamp;
+#endif
 	if (cmdiocbq->iocb_cmpl == NULL) {
 		if (cmdiocbq->wqe_cmpl) {
 			if (cmdiocbq->iocb_flag & LPFC_DRIVER_ABORTED) {
@@ -13304,7 +13309,7 @@ lpfc_sli4_nvmet_handle_rcqe(struct lpfc_hba *phba, struct lpfc_queue *cq,
 			dma_buf->bytes_recv = bf_get(lpfc_rcqe_length,  rcqe);
 			lpfc_nvmet_unsol_fcp_event(
 				phba, idx, dma_buf,
-				cq->assoc_qp->isr_timestamp);
+				cq->isr_timestamp);
 			return false;
 		}
 drop:
@@ -13479,6 +13484,12 @@ lpfc_sli4_hba_handle_eqe(struct lpfc_hba *phba, struct lpfc_eqe *eqe,
 
 	/* Process all the entries to the CQ */
 	while ((cqe = lpfc_sli4_cq_get(cq))) {
+#ifdef CONFIG_SCSI_LPFC_DEBUG_FS
+		if (phba->ktime_on)
+			cq->isr_timestamp = ktime_get_ns();
+		else
+			cq->isr_timestamp = 0;
+#endif
 		workposted |= lpfc_sli4_fp_handle_cqe(phba, cq, cqe);
 		if (!(++ecount % cq->entry_repost))
 			break;
@@ -13741,11 +13752,6 @@ lpfc_sli4_hba_intr_handler(int irq, void *dev_id)
 	if (unlikely(!fpeq))
 		return IRQ_NONE;
 
-#ifdef CONFIG_SCSI_LPFC_DEBUG_FS
-	if (phba->ktime_on)
-		fpeq->isr_timestamp = ktime_get_ns();
-#endif
-
 	if (lpfc_fcp_look_ahead) {
 		if (atomic_dec_and_test(&hba_eq_hdl->hba_eq_in_use))
 			lpfc_sli4_eq_clr_intr(fpeq);