On Sat, Apr 28, 2007 at 02:36:20AM +1000, David Chinner wrote: > The test was writing a single 50GB file to a fresh filesystem, and > then reading it back. Run on two different dm stripes - a 4-disk > RAID) and a 8disk RAID0 stripe, with a stripe unit of 512k. Disks > are 10krpm SAS, external jbod on PCI-X good for ~850MB/s read and > ~750MB/s write. Server is 4p intel x86_64 with 16GB RAM. > > READ WRITE > blksz disks tput sys tput sys > ----- ----- ----- ---- ----- ---- > 4k 4 332 35s 203 76s > 64k 4 173 20s 273 21s > 4k 8 403 35s 443 76s > 64k 8 634 21s 540 21s > > Throughput in MB/s.
Some more information - stripe unit on the dm raid0 is 512k. I have not attempted to increase I/O sizes at all yet - these test are just demonstrating efficiency improvements in the filesystem. These numbers for 32GB files. READ WRITE disks blksz tput sys tput sys ----- ----- ----- ---- ----- ---- 1 4k 89 18s 57 44s 1 16k 46 13s 67 18s 1 64k 75 12s 68 12s 2 4k 179 20s 114 43s 2 16k 55 13s 132 18s 2 64k 126 12s 126 12s 4 4k 350 20s 214 43s 4 16k 350 14s 264 19s 4 64k 176 11s 266 12s 8 4k 415 21s 446 41s 8 16k 655 13s 518 19s 8 64k 664 12s 552 12s 12 4k 413 20s 633 33s 12 16k 736 14s 741 19s 12 64k 836 12s 743 12s Throughput in MB/s. Consistent improvement across the write results, first time I've hit the limits of the PCI-X bus with a single buffered I/O thread doing either reads or writes. Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/