HD to SSD question.

[Heinz Diehl]

On 20.08.2013, Mihai T. Lazarescu wrote: 

> Here are the program numbers while running the script:
> 
> CFQ:
[....]

Seems that cfq performs better on your machine, under this workload.
Gave it a quick test (using the original fsync-tester from Ted Tso):

cfq:

htd at kiera test]$ ./fst1
fsync time: 3.3269
fsync time: 1.4869
fsync time: 2.4756
fsync time: 8.4763
fsync time: 11.4740
fsync time: 9.4753
fsync time: 16.4822
fsync time: 8.4712
^C

dl:

htd at kiera test]$ ./fst1
fsync time: 0.2231
fsync time: 1.1388
fsync time: 0.4851
fsync time: 2.1329
fsync time: 0.9891
fsync time: 0.5336
fsync time: 1.5352
fsync time: 0.3914
fsync time: 0.7822
^C

I run an OCZ Vertex 4, filesystem is XFS mounted with 
"rw,noatime,attr2,discard,nobarrier,inode64,logbufs=8,logbsize=256k,noquota".

These are my deadline parameters: 
echo "deadline" > /sys/block/sda/queue/scheduler
echo "0" > /sys/block/sda/queue/iosched/front_merges
echo "8" > /sys/block/sda/queue/iosched/fifo_batch

These are the disk "tunings":
/sbin/hdparm -W1 /dev/sda
/sbin/blockdev --setra 8192 /dev/sda