I think I found part of the bug for these metrics. The metrics are being
converted to milliseconds twice, in the sard patch and in the Linux pmda:
From sard patch:
+#define MSEC(x) ((x) * 1000 / HZ)
+ MSEC(hd->rd_ticks),
+ hd->wr_ios, hd->wr_merges,
+ hd->wr_sectors,
+ MSEC(hd->wr_ticks),
+ hd->ios_in_flight,
+ MSEC(hd->io_ticks),
+ MSEC(hd->aveq));
+#undef MSEC
From the Linux pmda:
case 46: /* disk.dev.avactive */
atom->ul = 1000 * p->io_ticks / proc_stat.hz;
break;
case 47: /* disk.dev.aveq */
atom->ul = 1000 * p->aveq / proc_stat.hz;
break;
case 44: /* disk.all.avactive */
atom->ull += 1000 * p->io_ticks / proc_stat.hz;
break;
case 45: /* disk.all.aveq */
atom->ull += 1000 * p->aveq / proc_stat.hz;
break;
Also shouldn't all the metrics be ull?
Todd C. Davis
These are my opinions and absolutely not official opinions of Intel Corp.
-----Original Message-----
From: Davis, Todd C
Sent: Tuesday, March 18, 2003 11:36 AM
To: 'pcp@xxxxxxxxxxx'
Subject: disk.dev.avactive and disk.dev.aveq on RH Advanced Server
With no disk activity on the system I see disk.dev.avactive and
disk.dev.aveq on the root drive. The last sample had some disk io but the
disk.dev.avactive number did not change and disk.dev.aveq number did not
change significantly. Are these metrics supposed to me accurate? They look
bogus to me.
I am running RetHat Advanced Sever with a 2.4.18 kernel with the sard patch
applied.
The script:
pmie -f -e -V <<pmie.end
//
// Watch average disk utilization and average queue length
//
myhost = "localhost"; // the host of interest
delta = 3 sec;
Block_total =
disk.dev.blktotal :\$myhost;
Average_disk_utilization =
disk.dev.avactive :\$myhost;
Average_queue_length =
disk.dev.aveq :\$myhost;
pmie.end
The output:
Block_total (Tue Mar 18 11:09:06 2003): ? ?
Average_disk_utilization (Tue Mar 18 11:09:06 2003): ? ?
Average_queue_length (Tue Mar 18 11:09:06 2003): ? ?
Block_total (Tue Mar 18 11:09:09 2003):
localhost: [sda] 0
localhost: [sdb] 0
Average_disk_utilization (Tue Mar 18 11:09:09 2003):
localhost: [sda] 10.0
localhost: [sdb] 0
Average_queue_length (Tue Mar 18 11:09:09 2003):
localhost: [sda] 30.1
localhost: [sdb] 0
Block_total (Tue Mar 18 11:09:12 2003):
localhost: [sda] 0
localhost: [sdb] 0
Average_disk_utilization (Tue Mar 18 11:09:12 2003):
localhost: [sda] 10.0
localhost: [sdb] 0
Average_queue_length (Tue Mar 18 11:09:12 2003):
localhost: [sda] 30.0
localhost: [sdb] 0
Block_total (Tue Mar 18 11:09:15 2003):
localhost: [sda] 0
localhost: [sdb] 0
Average_disk_utilization (Tue Mar 18 11:09:15 2003):
localhost: [sda] 10.0
localhost: [sdb] 0
Average_queue_length (Tue Mar 18 11:09:15 2003):
localhost: [sda] 30.0
localhost: [sdb] 0
Block_total (Tue Mar 18 11:09:18 2003):
localhost: [sda] 0
localhost: [sdb] 0
Average_disk_utilization (Tue Mar 18 11:09:18 2003):
localhost: [sda] 10.0
localhost: [sdb] 0
Average_queue_length (Tue Mar 18 11:09:18 2003):
localhost: [sda] 30.0
localhost: [sdb] 0
Block_total (Tue Mar 18 11:09:21 2003):
localhost: [sda] 85
localhost: [sdb] 0
Average_disk_utilization (Tue Mar 18 11:09:21 2003):
localhost: [sda] 10.0
localhost: [sdb] 0
Average_queue_length (Tue Mar 18 11:09:21 2003):
localhost: [sda] 30.9
localhost: [sdb] 0
Todd C. Davis
These are my opinions and absolutely not official opinions of Intel Corp.
Telco Systems Development
Intel Corporation, Columbia Design Center
CBA-2, Suite 100
250 Berry Hill Road
Columbia, SC 29210
(803) 461-6108
fax:: (803) 461-6292
mailto:todd.c.davis@xxxxxxxxx
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