Messages in this thread | | | Subject | RE: [PATCH 1/2] scsi: ufs: Introduce hba performance monitor sysfs nodes | From | Daejun Park <> | Date | Tue, 06 Apr 2021 13:11:40 +0900 |
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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? I think lat_sum should be 0 at this point.
> + } > + > +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?
> + 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.
> + > + m->nr_queued[dir]--; > + /* Push forward the busy start of monitor */ > + m->busy_start_ts[dir] = now; > + } > +}
Thanks, Daejun
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