Re: Rump FS throughput

[Thomas Klausner <wiz%NetBSD.org@localhost>]

On Thu, May 31, 2012 at 01:45:53PM -0400, Matthew Mondor wrote:
> Although it's useful to mount random media more safely than it would be
> using kernel-space, I noticed that using 64KB reads, the kernel cd9660
> will gladly read ~20MB/s from a DVD, but that rump_cd9660 using
> 64KB reads is limited to aproximately 4MB/s at most, even if the system
> is mostly idle during those transfers (on netbsd-6/amd64 and 4 3.3GHz
> cores).

Some suggestions from Antti via email proxy:
Maybe he is using the block device (/dev/cd0a) instead of the raw device
(/dev/rcd0a).  IIRC the former has some pretty serious performance
problems for userspace I/O.  Also in the "maybe" department, libp2k
should probably detect and autoadjust a block device to raw device.
Or, someone could just fix the bdev stuff.


Cheers,
 Thomas