On 9/26/19 7:10 AM, Karandeep Chahal wrote:
I am wondering why SRP REQ CM timeout is "subnet_timeout + 2". What was the
reason behind adding 2 to the subnet timeout? I think it was added by Bart
in commit 4c532d6ce14bb3fb4e1cb2d29fafdd7d6bded51c, but the commit message
does not explain why the 2 is necessary. Would anyone happen to know?
My understanding is that adding 2 causes the CM timeout value to become
4 times
the subnet_timeout value. Hence, even if you have a reasonable
subnet_timeout
the CM REQ timeout becomes too high.
Hi Karan,
I think the description of that commit explains why that change has been
made:
IB/srp: Make CM timeout dependent on subnet timeout
For small networks it is safe to reduce the subnet timeout from
its default value (18 for opensm) to 16. Make the SRP CM timeout
dependent on the subnet timeout such that decreasing the subnet
timeout also causes SRP failover and failback to occur faster.
Bart.
