On 15/11/2015 11:04, Or Gerlitz wrote:
On Sun, Nov 15, 2015 at 10:48 AM, Sagi Grimberg
<sagig@xxxxxxxxxxxxxxxxxx> wrote:
Or is correct,
I have attempted to convert iser to use blk_iopoll in the past, however
I've seen inconsistent performance and latency skews (comparing to
tasklets iser is using today). This was manifested in IOPs test cases
where I ran multiple threads with higher queue-depth and not in
sanitized pure latency (QD=1) test cases. Unfortunately I didn't have
the time to pick it up since.
I do have every intention of testing it again with this. If it still
exist we will need to find the root-cause of it before converting
drivers to use it.
Good, this way (inconsistent performance and latency skews) or another
(all shines up) -- please
let us know your findings, best through commenting within V > 0 the
cover letter posts of this series
Hi Or & Co,
I ran some tests on the iser code with this patchset applied.
I can confirm that I did not see any performance degradations.
summary (on my test servers):
1 LUN: ~530K (IOPs)
2 LUNs: ~1080K (IOPs)
4 LUNs: ~1350K (IOPs)
8 LUNs: ~1930K (IOPs)
16 LUns: ~2250K (IOPs)
These results are true both for tasklet and iopoll.
So, I don't have anything smart to say here, the IO
stack (block, scsi) has gone through major changes since
the last time I looked into this, so it'll be pretty hard to figure
out what was the root cause back then...
Sagi.
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