On Wed, Aug 22, 2001 at 06:15:37PM +0100, Ben wrote: > Hi, > > The speed of the ataraid driver seems to be a bit poorly :( > With my HPT370, I can get ~34Mbytes/second streaming off one of my > drives in Linux, but only ~25Mbytes/second when going via the > /dev/ataraid/d0 device. Any ideas for the slowdown? > > (Using ataraid from 2.4.8-ac7) there is a reason; the kernel does IO requests in blocks of 4 kilobyte. Due to having partitions, that 4Kb sometimes "overlaps" the 64Kb boundary that is typical for raid0. In that case, the driver has to split the request into 2 smaller ones, and it needs to allocate memory for that. I'm planning to make the driver have a stash of preallocated (and recycled) blocks of memory in order to make it not have to allocate new memory every 64Kb. Greetings, Arjan van de Ven
