Ubuntu
linux package

  1. Bug #620074
  2. Comment #606

Comment 606 for bug 620074

Revision history for this message
In , kernel (kernel-linux-kernel-bugs) wrote :

(In reply to comment #592)
> [...] devices which have NCQ support not needing in schedulers [...]
>
> Seems all my devices support NCQ. I manually set noop sheduler, and system
> was
> apparently much responsible. [...]

While it is true that the hard drive will reorder I/O requests within its native command queue to optimize armature movements, the on-device queue is really very shallow (only 32 requests maximum on your hardware). By circumventing the kernel's I/O scheduler (by selecting "noop"), you are losing the benefits of merging adjacent I/O requests and of distributing I/O throughput fairly across multiple processes.