Hi Daejun,
On 2021-04-06 12:11, Daejun Park wrote:
Hi Can Guo,
+static ssize_t monitor_enable_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct ufs_hba *hba = dev_get_drvdata(dev);
+ unsigned long value, flags;
+
+ if (kstrtoul(buf, 0, &value))
+ return -EINVAL;
+
+ value = !!value;
+ spin_lock_irqsave(hba->host->host_lock, flags);
+ if (value == hba->monitor.enabled)
+ goto out_unlock;
+
+ if (!value) {
+ memset(&hba->monitor, 0, sizeof(hba->monitor));
+ } else {
+ hba->monitor.enabled = true;
+ hba->monitor.enabled_ts = ktime_get();
How about setting lat_max to and lat_min to KTIME_MAX and 0?
lat_min is already 0. What is the benefit of setting lat_max to
KTIME_MAX?
I think lat_sum should be 0 at this point.
lat_sum is already 0 at this point, what is the problem?
+ }
+
+out_unlock:
+ spin_unlock_irqrestore(hba->host->host_lock, flags);
+ return count;
+}
+static void ufshcd_update_monitor(struct ufs_hba *hba, struct
ufshcd_lrb *lrbp)
+{
+ int dir = ufshcd_monitor_opcode2dir(*lrbp->cmd->cmnd);
+
+ if (dir >= 0 && hba->monitor.nr_queued[dir] > 0) {
+ struct request *req = lrbp->cmd->request;
+ struct ufs_hba_monitor *m = &hba->monitor;
+ ktime_t now, inc, lat;
+
+ now = ktime_get();
How about using lrbp->compl_time_stamp instead of getting new value?
I am expecting "now" keeps increasing and use it to update
m->busy_start_s,
but if I use lrbp->compl_time_stamp to do that, below line ktime_sub()
may
give me an unexpected value as lrbp->compl_time_stamp may be smaller
than
m->busy_start_ts, because the actual requests are not completed by the
device
in the exact same ordering as the bits set in hba->outstanding_tasks,
but driver
is completing them from bit 0 to bit 31 in ascending order.
+ inc = ktime_sub(now, m->busy_start_ts[dir]);
+ m->total_busy[dir] = ktime_add(m->total_busy[dir],
inc);
+ m->nr_sec_rw[dir] += blk_rq_sectors(req);
+
+ /* Update latencies */
+ m->nr_req[dir]++;
+ lat = ktime_sub(now, lrbp->issue_time_stamp);
+ m->lat_sum[dir] += lat;
+ if (m->lat_max[dir] < lat || !m->lat_max[dir])
+ m->lat_max[dir] = lat;
+ if (m->lat_min[dir] > lat || !m->lat_min[dir])
+ m->lat_min[dir] = lat;
This if statement can be shorted, by setting lat_max / lat_min as
default value.
I don't quite get it, can you show me the code sample?
Thanks,
Can Guo
+
+ m->nr_queued[dir]--;
+ /* Push forward the busy start of monitor */
+ m->busy_start_ts[dir] = now;
+ }
+}
Thanks,
Daejun
