[PATCH 0/1] libata: Get rid of ata_port::qc_allocated bitmask

From: Alexander Gordeev
Date: Tue Jan 21 2014 - 10:00:54 EST


Hi Tejun,

This update is against "scsi-mq" branch in Nicholas tree:
git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending.git

A quick check with 'fio' tool's random reading indicates an
moderate improvement on a single drive, four threads and the
queue depth of 32:

read : io=131072KB, bw=149785B/s, iops=36, runt=896066msec

vs

read : io=131072KB, bw=166884B/s, iops=40, runt=804257msec

I have not measured cache line bouncing itself. I am kind of
limited in hardware configurations, but let me know if you
want to see more testing anyway.

Thanks!

Alexander Gordeev (1):
libata: Get rid of ata_port::qc_allocated bitmask

drivers/ata/libata-core.c | 82 +++++++++++++++++++++++++++++++-------------
include/linux/libata.h | 6 ++-
2 files changed, 62 insertions(+), 26 deletions(-)

--
1.7.7.6

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