diff --git a/srpt/README b/srpt/README index 7b43baf7c..1d86add1b 100644 --- a/srpt/README +++ b/srpt/README @@ -343,6 +343,13 @@ Performance Notes - Target Side Performance Notes - Initiator Side ---------------------------------- +* Choose a proper value for the ib_srp kernel module parameter + cmd_sg_entries. The default value 12 works well for buffered reads while + the throughput for write-dominated workloads improves by changing this value + into 255. One way to set this kernel module parameter is as follows: + + echo options ib_srp cmd_sg_entries=255 >>/etc/modprobe.d/ib_srp.conf + * For multithreaded workloads using small block sizes changing rq_affinity into 2 improves IOPS significantly (Linux kernel 3.1 and later; see also commit 5757a6d76cdf6dda2a492c09b985c015e86779b1).