Comment 323 for bug 620074

(In reply to comment #306)
> You're running a kernel that is known to have high write latencies, and it
> doesn't appear that your fsync latency test is running in parallel with the
> dd.

????????????????????????????
Most likely about it is not known to anybody. The bug status 'NEW'.

> With 8GB of RAM, you likely need to change your dd to write out at least
> 10GB
> of data instead of 5GB.

OK (add for (In reply to comment #304))

dd if=/dev/zero of=./bigfile bs=1M count=15000 & ./fsync-tester
...
fsync time: 2.3800
fsync time: 2.4295
fsync time: 2.4099
fsync time: 2.1599
fsync time: 2.0760
fsync time: 2.6152
fsync time: 2.1427
fsync time: 2.4893
fsync time: 2.3252
fsync time: 2.3208
fsync time: 2.4223
...
fsync time: 2.3710
fsync time: 1.3094
fsync time: 1.4473
fsync time: 2.7260
fsync time: 2.2739
fsync time: 2.2078
fsync time: 0.5446
15000+0 records in
15000+0 records out
fsync time: 1.5607
15728640000 bytes (16 GB) copied, 201,724 s, 78,0 MB/s

procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r b swpd free buff cache si so bi bo in cs us sy id wa
 0 5 0 3930476 6108 3873852 0 0 0 74384 883 1632 1 4 0 94
 0 5 0 3864644 6108 3941216 0 0 0 64512 667 1088 1 5 0 93
 0 4 0 3788956 6108 4015088 0 0 0 73728 943 1738 2 5 0 93
 0 5 0 3735848 6108 4070376 0 0 0 53268 666 1181 1 5 0 94
 2 5 0 3671468 6108 4135384 0 0 0 65024 735 1277 1 4 0 94
 0 4 0 3590356 6108 4213988 0 0 0 77824 860 1590 2 5 0 93
 1 5 0 3524484 6108 4280384 0 0 0 64392 749 1495 1 4 0 94