On Fri, Jul 6, 2012 at 5:38 AM, majianpeng <majianpeng@xxxxxxxxx> wrote: > To imporve write performance and as posssible as to achieve full-write, > it only fetch IO_THRESHOLD stripes from delay_list to hold_list. > > Signed-off-by: majianpeng <majianpeng@xxxxxxxxx> Yes, I do think we need something like this to further limit the maximum in-flight pre-read, especially for the async / multithread xor case where we process stripes faster. However, this is the job of get_priority_stripe(), not raid5_activate_delayed(), to rate limit pre-reads versus full stripes. One pre-read stripe at a time seems to over bias full stripe writes. I wonder if you see the same performance effect by echo 0 > /sys/block/<mddev>/md/preread_bypass_threshold? -- Dan -- 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
