On Wed, Aug 31 2005, jmerkey wrote: > > > I have seen an 80GB/sec limitation in the kernel unless this value is > changed in the SCSI I/O layer > for 3Ware and other controllers during testing of 2.6.X series kernels. > > Change these values in include/linux/blkdev.h and performance goes from > 80MB/S to over 670MB/S on the 3Ware controller. > > > //#define BLKDEV_MIN_RQ 4 > //#define BLKDEV_MAX_RQ 128 /* Default maximum */ > #define BLKDEV_MIN_RQ 4096 > #define BLKDEV_MAX_RQ 8192 /* Default maximum */ That's insane, you just wasted 1MiB of preallocated requests on each queue in the system! Please just do # echo 512 > /sys/block/dev/queue/nr_requests after boot for each device you want to increase the queue size too. 512 should be enough with the 3ware. -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
