On 9/23/2014 10:02 PM, Bart Van Assche wrote:
On 23/09/2014 10:32, Sagi Grimberg wrote:
On 9/19/2014 4:00 PM, Bart Van Assche wrote:
Improve performance by using multiple RDMA/RC channels per SCSI host
for communicating with an SRP target.
Hey Bart,
Since you don't seem to negotiate/declare multichannel with the target,
did you test this code with some target implementations other than SCST
that happen to be out there?
Overall, I think this patch would be easier to review if you also
provide a list of logical changes (which obviously are introduced in
this patch). Patch 7/8 can use some more information of target-channel
relations as well.
Hello Sagi,
That's a good question. So far this patch series has only been tested
against the SCST SRP target driver. However, as you probably noticed, if
setting up a second or later RDMA channel fails SRP login is not failed
but communication proceeds with the number of channels that have been
established. This mechanism should retain backwards compatibility with
SRP target systems that do not support multichannel communication.
However, if the new code for SRP login turns out to be triggering bugs
in existing SRP target implementations we can still add a blacklist for
these implementations.
I'm more concerned that a target will accept multichannel and then
starts flipping since that wasn't tested in I don't know when, probably
never...
Since SRP_LOGIN_REQ/RESP has some free bits why not declare it and
activate it when both sides *says* they support it? I'd be much calmer
knowing we're on the safe side on this...
I will provide a more detailed list of logical changes in the second
version of this patch series.
Thanks,
Plus, I would like to run it on my performance setups. can you point me
to the SCST repo? is multichannel supported in scst trunk?
Sagi.
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