Hi, Hannes:
On 06/06/2013 05:43 PM, Hannes Reinecke wrote:
this is the first step towards a new non-blocking
error handler. This patch implements a new command
timeout handler which will be sending command aborts
inline without engaging SCSI EH.
In addition the commands will be returned directly
if the command abort succeeded, cutting down recovery
times dramatically.
With the original scsi error recovery I got:
# time dd if=/dev/zero of=/mnt/test.blk bs=512 count=2048 oflag=sync
2048+0 records in
2048+0 records out
1048576 bytes (1.0 MB) copied, 3.72732 s, 281 kB/s
real 2m14.475s
user 0m0.000s
sys 0m0.104s
with this patchset I got:
# time dd if=/dev/zero of=/mnt/test.blk bs=512 count=2048 oflag=sync
2048+0 records in
2048+0 records out
1048576 bytes (1.0 MB) copied, 31.5151 s, 33.3 kB/s
real 0m31.519s
user 0m0.000s
sys 0m0.088s
Test was to disable RSCN on the target port, disable the
target port, and then start the 'dd' command as indicated.
As a proof-of-concept I've also enabled the new timeout
handler for virtio, so that things can be tested out
more easily.
So this 31.5s is tested on virtio disks, right? Much faster than your
former test via fc.
This approach may not work for some LLDDs as you said, but I wonder
whether SAS is applicable(whether there will be later patches for
SAS).
Thanks,
Ren
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