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| author | Ming Lei <ming.lei@redhat.com> | 2017-07-05 12:14:27 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2017-07-05 12:11:26 -0600 |
| commit | 8a05aa4ce3bf767b7bd72851da89c23d084d1ecb (patch) | |
| tree | 2ad465f735488c668d1193d02c066ba3f3b00863 /kernel/kexec_internal.h | |
| parent | ea4d12dabf872b496218cdc8e7874feef8676cdd (diff) | |
| download | linux-8a05aa4ce3bf767b7bd72851da89c23d084d1ecb.tar.gz linux-8a05aa4ce3bf767b7bd72851da89c23d084d1ecb.tar.bz2 linux-8a05aa4ce3bf767b7bd72851da89c23d084d1ecb.zip | |
mtip32xx: avoid to read HOST_CAP from HW in .queue_rq()
It is observed reading the register from HW takes a bit long,
for example in my box, the following difference of 'perf report
--no-children fio ...' can be seen when running I/O:
1) V4.12 without patch
+ 9.28% fio [mtip32xx] [k] mtip_irq_handler
+ 8.48% fio [mtip32xx] [k] mtip_init_cmd_header
2) V4.12 with the following patch
+ 9.14% fio [mtip32xx] [k] mtip_irq_handler
......
+ 1.14% fio [mtip32xx] [k] mtip_init_cmd_header
IOPS can be increased by ~5% with this patch too.
Fixes: a4e84aae8139(mtip32xx: use runtime tag to initialize command header)
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'kernel/kexec_internal.h')
0 files changed, 0 insertions, 0 deletions