[ofa-general] SRP and sync

[Kevin Harms]

  I'm doing some testing of direct attached storage using SRP. When I use 'sync', the write performance drops off significantly below what the device is capable of for a given sustained write. The read shows something more along the lines of the expected performance. I'm using OFED 1.2.5.5. Is there some issue with OFED and using sync?

thanks,
Kevin Harms

fs121: # sg_dd if=/dev/zero of=dd.test oflag=dsync bs=4096 bpt=512 count=10000 time=1
 time to transfer data: 0.721404 secs at 56.78 MB/sec
10000+0 records in
10000+0 records out
fs121: # sync
fs121: # sysctl -w vm.drop_caches=1
vm.drop_caches = 1
fs121: # sysctl -w vm.drop_caches=2
vm.drop_caches = 2
fs121: # sysctl -w vm.drop_caches=3
vm.drop_caches = 3
fs121: # sg_dd of=/dev/zero if=dd.test bs=4096 bpt=512 count=10000 time=1
 time to transfer data: 0.091308 secs at 448.59 MB/sec
10000+0 records in
10000+0 records out