pt-diskstats shows incorrect wr_mb_s
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Percona Toolkit moved to https://jira.percona.com/projects/PT |
Fix Released
|
Medium
|
Baron Schwartz | ||
2.0 |
Fix Released
|
Medium
|
Baron Schwartz | ||
2.1 |
Fix Released
|
Medium
|
Baron Schwartz |
Bug Description
iostat -dxm 5 shows:
Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sdb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
scd0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
fioa 0.00 0.00 0.00 7765.00 0.00 121.32 32.00 0.00 4.02 0.00 0.00
fiob 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 0.20 0.00 0.60 0.00 0.00 10.67 0.00 0.00 0.00 0.00
sdb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
scd0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
fioa 0.00 0.00 0.00 7540.40 0.00 117.82 32.00 0.00 4.00 0.00 0.00
fiob 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sdb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
scd0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
fioa 0.00 0.00 0.00 7500.20 0.00 117.18 32.00 0.00 3.98 0.00 0.00
fiob 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 0.20 0.00 0.60 0.00 0.00 10.67 0.00 0.00 0.00 0.00
sdb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
scd0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
fioa 0.00 0.00 0.00 7452.80 0.00 116.44 32.00 20.08 4.03 0.02 15.94
fiob 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Device: rrqm/s wrqm/s r/s w/s rMB/s wMB/s avgrq-sz avgqu-sz await svctm %util
sda 6.20 0.00 0.80 0.20 0.03 0.00 57.60 0.03 31.80 22.00 2.20
sdb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
scd0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
fioa 0.00 0.00 0.00 7450.40 0.00 116.41 32.00 20.22 4.02 0.02 15.92
fiob 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
pt-diskstat shows
#ts device rd_s rd_avkb rd_mb_s rd_mrg rd_cnc rd_rt wr_s wr_avkb wr_mb_s wr_mrg wr_cnc wr_rt busy in_prg io_s qtime stime
{160} fioa 0.1 4.0 0.0 0% 0.0 26.6 30924.6 6.0 181.5 0% 777.5 25.1 47% 0 30924.6 23.3 0.0
{161} fioa 0.1 4.0 0.0 0% 0.0 26.6 30778.5 6.0 181.1 0% 772.9 25.1 47% 0 30778.6 23.2 0.0
{162} fioa 0.1 4.0 0.0 0% 0.0 26.6 30634.3 6.0 180.7 0% 768.3 25.1 46% 0 30634.4 23.2 0.0
{163} fioa 0.1 4.0 0.0 0% 0.0 26.6 30492.0 6.1 180.3 0% 763.7 25.0 46% 0 30492.1 23.1 0.0
{164} fioa 0.1 4.0 0.0 0% 0.0 26.6 30352.7 6.1 179.9 0% 759.2 25.0 46% 0 30352.8 23.1 0.0
while sysbench is:
[ 280s] reads: 0.00 MB/s writes: 120.01 MB/s fsyncs: 0.00/s response time: 0.045ms (95%)
[ 290s] reads: 0.00 MB/s writes: 116.24 MB/s fsyncs: 0.00/s response time: 0.045ms (95%)
[ 300s] reads: 0.00 MB/s writes: 121.96 MB/s fsyncs: 0.00/s response time: 0.045ms (95%)
[ 310s] reads: 0.00 MB/s writes: 118.33 MB/s fsyncs: 0.00/s response time: 0.045ms (95%)
[ 320s] reads: 0.00 MB/s writes: 114.20 MB/s fsyncs: 0.00/s response time: 0.045ms (95%)
[ 330s] reads: 0.00 MB/s writes: 118.77 MB/s fsyncs: 0.00/s response time: 0.045ms (95%)
[ 340s] reads: 0.00 MB/s writes: 119.28 MB/s fsyncs: 0.00/s response time: 0.045ms (95%)
so device is doing close to 120 MB/s,
while
pt-diskstats shows 180
I am using async io mode in sysbench
Related branches
- Daniel Nichter: Approve
-
Diff: 36 lines (+9/-5)2 files modifiedbin/pt-diskstats (+6/-5)
t/pt-query-digest/mirror.t (+3/-0)
- Daniel Nichter: Approve
-
Diff: 36 lines (+9/-5)2 files modifiedbin/pt-diskstats (+6/-5)
t/pt-query-digest/mirror.t (+3/-0)
tags: | added: pt-diskstats wrong-output |
I have an impression that
pt-diskstat
shows stats (at least wr_mb_s ) as an average from timestamp #1.
Which does not make much sense, because while pt-diskstat is running
I may change a workload significantly, and I am interested to see the actual current stats, not averages from
some earlier point of time.