From 50dc64fd1c4d16416748dd9ad70bc462eddebd79 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Sun, 13 Dec 2009 18:01:14 +0000 Subject: [PATCH] Updated SRPT documentation. git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@1389 d57e44dd-8a1f-0410-8b47-8ef2f437770f --- srpt/README | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/srpt/README b/srpt/README index 174888604..5f74e85f0 100644 --- a/srpt/README +++ b/srpt/README @@ -39,6 +39,10 @@ Proceed as follows to compile and install the SRP target driver: helps to avoid QUEUE_FULL conditions because the size of the transmit queue in Linux' SRP initiator is also 64. + Note: the SCSI layer of kernel 2.6.33 will have dynamic queue depth + adjustment. When using SRP initiator systems with kernel 2.6.33 or later, + this patch is less important. + 2. Now compile and install SRPT: cd ${SCST_DIR} @@ -139,11 +143,20 @@ Notes: on how to enable and how to use the HA feature. See e.g. http://www.mellanox.com/related-docs/prod_software/Mellanox_OFED_Linux_user_manual_1_40_1.pdf. -Performance notes ------------------ +Performance Notes - Initiator Side +---------------------------------- * For latency sensitive applications, using the noop scheduler at the initiator - side can give significantly better resuts than with other schedulers. + side can give significantly better results than with other schedulers. + +* The following parameters have a small but measureable impact on SRP + performance: + * /sys/class/block/${dev}/queue/rq_affinity + * /proc/irq/${ib_int_no}/smp_affinity + + +Performance Notes - Target Side +---------------------------------- * In some cases, for instance working with SSD devices, which consume 100% of a single CPU load for data transfers in their internal threads, to