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author | Jens Axboe <jens.axboe@oracle.com> | 2008-09-13 20:26:01 +0200 |
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committer | Jens Axboe <jens.axboe@oracle.com> | 2008-10-09 08:56:09 +0200 |
commit | c7c22e4d5c1fdebfac4dba76de7d0338c2b0d832 (patch) | |
tree | ecc3d2517b3471ccc35d4cb4e3b48d4b57205061 /fs | |
parent | block: make kblockd_schedule_work() take the queue as parameter (diff) | |
download | linux-c7c22e4d5c1fdebfac4dba76de7d0338c2b0d832.tar.xz linux-c7c22e4d5c1fdebfac4dba76de7d0338c2b0d832.zip |
block: add support for IO CPU affinity
This patch adds support for controlling the IO completion CPU of
either all requests on a queue, or on a per-request basis. We export
a sysfs variable (rq_affinity) which, if set, migrates completions
of requests to the CPU that originally submitted it. A bio helper
(bio_set_completion_cpu()) is also added, so that queuers can ask
for completion on that specific CPU.
In testing, this has been show to cut the system time by as much
as 20-40% on synthetic workloads where CPU affinity is desired.
This requires a little help from the architecture, so it'll only
work as designed for archs that are using the new generic smp
helper infrastructure.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/bio.c | 1 |
1 files changed, 1 insertions, 0 deletions
@@ -111,6 +111,7 @@ void bio_init(struct bio *bio) { memset(bio, 0, sizeof(*bio)); bio->bi_flags = 1 << BIO_UPTODATE; + bio->bi_comp_cpu = -1; atomic_set(&bio->bi_cnt, 1); } |