[PATCH 2/6] lpfc: Correct bandwidth logging during receipt of congestion sync WCQE

Justin Tee
2022-11-16T01:11:00Z

The lpfc_cmf_timer adjusts phba->cmf_link_byte_count periodically and
can artifically inflate bandwidth percent.

During bandwidth calculation, correct for this by setting a cap of logging
a maximum of 100%.

Bandwidth calculation is only used for display under LOG_CGN_MGMT so there
is no expectation of impacts on performance.

Signed-off-by: Justin Tee <justin.tee@broadcom.com>
---
drivers/scsi/lpfc/lpfc_sli.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c
index d25afc9dde14..a66026432572 100644
--- a/drivers/scsi/lpfc/lpfc_sli.c
+++ b/drivers/scsi/lpfc/lpfc_sli.c
@@ -1848,6 +1848,12 @@ lpfc_cmf_sync_cmpl(struct lpfc_hba *phba, struct lpfc_iocbq *cmdiocb,
phba->cmf_link_byte_count);
bwpcent = div64_u64(bw * 100 + slop,
phba->cmf_link_byte_count);
+ /* Because of bytes adjustment due to shorter timer in
+ * lpfc_cmf_timer() the cmf_link_byte_count can be shorter and
+ * may seem like BW is above 100%.
+ */
+ if (bwpcent > 100)
+ bwpcent = 100;

if (phba->cmf_max_bytes_per_interval < bw &&
bwpcent > 95)
--
2.38.0