Awful FreeBSD 9 block IO performance in KVM

Wojciech Puchar wojtek at wojtek.tensor.gdynia.pl
Sun Jul 22 07:21:40 UTC 2012


>
> 2) That's roughly the speed I'd expect without queueing. Is it really
> making effective use of queueing, or is something limiting queueing to
> one transfer at a time?
still 400-500 IOPS is way too little.

FreeBSD without VM machine can do well over 10000 IOPS of 512 byte 
sequential read with single process on my laptop using less than 20% of 
single not blazing fast CPU.

dd if=/dev/ada0 of=/dev/null bs=512
117593+0 records in
117593+0 records out
60207616 bytes transferred in 7.709451 secs (7809585 bytes/sec)

CPU: Pentium(R) Dual-Core CPU       T4500  @ 2.30GHz (2294.56-MHz K8-class CPU)



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