On Wed, Apr 17, 2013 at 07:04:51PM +0200, Roger Pau Monné wrote: > On 17/04/13 16:25, Konrad Rzeszutek Wilk wrote: > >>> Perhaps the xen-blkfront part of the patch should be just split out to > >>> make > >>> this easier? > >>> > >>> Perhaps what we really should have is just the 'max' value of megabytes > >>> we want to handle on the ring. > >>> > >>> As right now 32 ring requests * 32 segments = 4MB. But if the user wants > >>> to se the max: 32 * 4096 = so 512MB (right? each request would handle now > >>> 16MB > >>> and since we have 32 of them = 512MB). > >> > >> I've just set that to something that brings a performance benefit > >> without having to map an insane number of persistent grants in blkback. > >> > >> Yes, the values are correct, but the device request queue (rq) is only > >> able to provide read requests with 64 segments or write requests with > >> 128 segments. I haven't been able to get larger requests, even when > >> setting this to 512 or higer. > > > > What are you using to drive the requests? 'fio'? > > Yes, I've tried fio with several "bs=" values, but it doesn't seem to > change the size of the underlying requests. Have you been able to get > bigger requests?
Martin, Jens, Any way to drive more than 128 segments? -- 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/
