Re: Amazon EC2 CPU Utilization

Greg Smith <greg <at> 2ndquadrant.com> writes:
> Could you try this again with "top -c", which will label these
> postmaster processes usefully, and include the pgbench client itself in
> what you post? It's hard to sort out what's going on in these
> situations without that style of breakdown.

As a further experiment, I ran 8 pgbench processes in parallel. The result is
about the same.

top - 18:34:15 up 17 min, 2 users, load average: 0.39, 0.40, 0.36
Tasks: 217 total, 8 running, 209 sleeping, 0 stopped, 0 zombie
Cpu(s): 22.2%us, 8.9%sy, 0.0%ni, 68.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.3%st
Mem: 7358492k total, 1611148k used, 5747344k free, 11416k buffers
Swap: 0k total, 0k used, 0k free, 1248408k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND


1506 postgres 20 0 197m 134m 132m S 29.4 1.9 0:09.27 postgres: postgres
postgres [local] idle

1524 postgres 20 0 197m 134m 132m R 29.4 1.9 0:05.13 postgres: postgres
postgres [local] idle

1509 postgres 20 0 197m 134m 132m R 27.1 1.9 0:08.58 postgres: postgres
postgres [local] SELECT

1521 postgres 20 0 197m 134m 132m R 26.4 1.9 0:05.77 postgres: postgres
postgres [local] SELECT

1512 postgres 20 0 197m 134m 132m S 26.1 1.9 0:07.62 postgres: postgres
postgres [local] idle

1520 postgres 20 0 197m 134m 132m R 25.8 1.9 0:05.31 postgres: postgres
postgres [local] idle

1515 postgres 20 0 197m 134m 132m S 23.8 1.9 0:06.94 postgres: postgres
postgres [local] SELECT

1527 postgres 20 0 197m 134m 132m S 21.8 1.9 0:04.46 postgres: postgres
postgres [local] SELECT

1517 postgres 20 0 49808 2012 1544 R 5.3 0.0 0:01.02 pgbench -S -c 1 -T
30

1507 postgres 20 0 49808 2012 1544 R 4.6 0.0 0:01.70 pgbench -S -c 1 -T
30

1510 postgres 20 0 49808 2008 1544 S 4.3 0.0 0:01.32 pgbench -S -c 1 -T
30

1525 postgres 20 0 49808 2012 1544 S 4.3 0.0 0:00.79 pgbench -S -c 1 -T
30

1516 postgres 20 0 49808 2016 1544 S 4.0 0.0 0:01.00 pgbench -S -c 1 -T
30

1504 postgres 20 0 49808 2012 1544 R 3.3 0.0 0:01.81 pgbench -S -c 1 -T
30

1513 postgres 20 0 49808 2016 1544 S 3.0 0.0 0:01.07 pgbench -S -c 1 -T
30

1522 postgres 20 0 49808 2012 1544 S 3.0 0.0 0:00.86 pgbench -S -c 1 -T
30

1209 postgres 20 0 63148 1476 476 S 0.3 0.0 0:00.11 postgres: stats
collector process