On Wed, Oct 28, 2009 at 7:47 PM, Chris Worley <[email protected]> wrote: > It appears that SRP tries to coalesce and fragment initiator I/O > requests into 64KB packets, as that looks to be the size requested > to/from the device on the target side (and the I/O scheduler is > disabled on the target). > > Is there a way to control this, where no coalescing occurs when > latency is an issue and requests are small, and no fragmentation > occurs when requests are large? > > Or, am I totally wrong in my assumption that SRP is coalescing/fragmenting > data?
Regarding avoiding coalescing of I/O requests: which I/O scheduler is being used on the initiator system and how has it been configured via sysfs ? Adjusting the constant MAX_RDMA_SIZE in scst/srpt/src/ib_srpt.h might help to avoid fragmentation of large requests by the SRP protocol. Please post a follow-up message to the mailing list with your findings such that MAX_RDMA_SIZE can be converted from a compile-time constant to a sysfs variable if this would be useful. Bart. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
