Il 14/08/2014 12:46, Kevin Wolf ha scritto:
> So to finally reply with some numbers... I'm running fio tests based on
> Ming's configuration on a loop-mounted tmpfs image using dataplane.
I'm not sure tmpfs is a particularly useful comparison, since it doesn't
support O_DIRECT. O_DIRECT over ramdisk ("modprobe brd rd_nr=1
rd_size=524288 max_part=1", either directly or via a filesystem) is
probably a better benchmark.
Also, I'm not sure how the I/O scheduler works over tmpfs. A ramdisk
should just do the right thing. (Are you using deadline or cfq?)
> | Random throughput | Sequential throughput
> ----------------+-------------------+-----------------------
> master | 442 MB/s | 730 MB/s
> base | 453 MB/s | 757 MB/s
> bypass (Ming) | 461 MB/s | 734 MB/s
> coroutine | 468 MB/s | 716 MB/s
> bypass (Paolo) | 476 MB/s | 682 MB/s
This is pretty large, but it really smells like either a setup problem
or a kernel bug...
Paolo
