scsi: fnic: fnic stats for max CQs processed and ISR time

This change is to add fnic stats for the max number of CQs (corresponding
to copy WQ) processed in a given interrupt, max time taken by the ISR.
Signed-off-by: Satish Kharat <satishkh@cisco.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/fnic/fnic_scsi.c

@@ -1325,13 +1325,32 @@ int fnic_wq_copy_cmpl_handler(struct fnic *fnic, int copy_work_to_do)
 	unsigned int wq_work_done = 0;
 	unsigned int i, cq_index;
 	unsigned int cur_work_done;
+	struct misc_stats *misc_stats = &fnic->fnic_stats.misc_stats;
+	u64 start_jiffies = 0;
+	u64 end_jiffies = 0;
+	u64 delta_jiffies = 0;
+	u64 delta_ms = 0;
 
 	for (i = 0; i < fnic->wq_copy_count; i++) {
 		cq_index = i + fnic->raw_wq_count + fnic->rq_count;
+
+		start_jiffies = jiffies;
 		cur_work_done = vnic_cq_copy_service(&fnic->cq[cq_index],
 						     fnic_fcpio_cmpl_handler,
 						     copy_work_to_do);
+		end_jiffies = jiffies;
+
 		wq_work_done += cur_work_done;
+		delta_jiffies = end_jiffies - start_jiffies;
+		if (delta_jiffies >
+			(u64) atomic64_read(&misc_stats->max_isr_jiffies)) {
+			atomic64_set(&misc_stats->max_isr_jiffies,
+					delta_jiffies);
+			delta_ms = jiffies_to_msecs(delta_jiffies);
+			atomic64_set(&misc_stats->max_isr_time_ms, delta_ms);
+			atomic64_set(&misc_stats->corr_work_done,
+					cur_work_done);
+		}
 	}
 	return wq_work_done;
 }

drivers/scsi/fnic/fnic_stats.h

@@ -97,6 +97,9 @@ struct vlan_stats {
 struct misc_stats {
 	u64 last_isr_time;
 	u64 last_ack_time;
+	atomic64_t max_isr_jiffies;
+	atomic64_t max_isr_time_ms;
+	atomic64_t corr_work_done;
 	atomic64_t isr_count;
 	atomic64_t max_cq_entries;
 	atomic64_t ack_index_out_of_range;

drivers/scsi/fnic/fnic_trace.c

@@ -409,6 +409,9 @@ int fnic_get_stats_data(struct stats_debug_info *debug,
 	len += snprintf(debug->debug_buffer + len, buf_size - len,
 		  "Last ISR time: %llu (%8llu.%09lu)\n"
 		  "Last ACK time: %llu (%8llu.%09lu)\n"
+		  "Max ISR jiffies: %llu\n"
+		  "Max ISR time (ms) (0 denotes < 1 ms): %llu\n"
+		  "Corr. work done: %llu\n"
 		  "Number of ISRs: %lld\n"
 		  "Maximum CQ Entries: %lld\n"
 		  "Number of ACK index out of range: %lld\n"
@@ -428,6 +431,9 @@ int fnic_get_stats_data(struct stats_debug_info *debug,
 		  (s64)val1.tv_sec, val1.tv_nsec,
 		  (u64)stats->misc_stats.last_ack_time,
 		  (s64)val2.tv_sec, val2.tv_nsec,
+		  (u64)atomic64_read(&stats->misc_stats.max_isr_jiffies),
+		  (u64)atomic64_read(&stats->misc_stats.max_isr_time_ms),
+		  (u64)atomic64_read(&stats->misc_stats.corr_work_done),
 		  (u64)atomic64_read(&stats->misc_stats.isr_count),
 		  (u64)atomic64_read(&stats->misc_stats.max_cq_entries),
 		  (u64)atomic64_read(&stats->misc_stats.ack_index_out_of_range),