| commit | c7c22e4d5c1fdebfac4dba76de7d0338c2b0d832 | |
| author | Jens Axboe <jens.axboe@oracle.com> | |
| Sat, 13 Sep 2008 18:26:01 +0000 (13 20:26 +0200) | ||
| committer | Jens Axboe <jens.axboe@oracle.com> | |
| Thu, 9 Oct 2008 06:56:09 +0000 (9 08:56 +0200) | ||
| tree | ecc3d2517b3471ccc35d4cb4e3b48d4b57205061 | treesnapshot (tar.gz zip) |
| parent | 18887ad910e56066233a07fd3cfb2fa11338b782 | commitdiff |
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>
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>