On 2011-07-25 03:14, Shaohua Li wrote: > 2011/7/24 Jens Axboe <jaxboe@xxxxxxxxxxxx>: >> On 2011-07-22 22:59, Dan Williams wrote: >>> Some storage controllers benefit from completions always being steered >>> to the strict requester cpu rather than the looser "per-socket" steering >>> that blk_cpu_to_group() attempts by default. >>> >>> echo 2 > /sys/block/<bdev>/queue/rq_affinity >> >> I have applied this one, with a modified patch description. >> >> I like the adaptive solution, but it should be rewritten to not declare >> and expose softirq internals. Essentially have an API from >> kernel/softirq.c that can return whether a given (or perhaps just local) >> softirq handler is busy or not. > Jens, > I posted a similar patch about two years ago( > http://marc.info/?l=linux-kernel&m=126136252929329&w=2). > At that time, you actually did a lot of tests and said the same cpu > approach will cause huge lock contention and bounce. Is that get fixed? Yep, it's not ideal. But if we are running out of steam on a single processor, there's really not much of an option currently. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
