From 3562037277f6f51c7b9ec551d2cf7ca3e13df013 Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bvanassche@acm.org>
Date: Sat, 23 Jan 2021 16:59:56 +0000
Subject: [PATCH 1/2] nightly build: Update kernel versions

git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@9337 d57e44dd-8a1f-0410-8b47-8ef2f437770f
---
 nightly/conf/nightly.conf | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/nightly/conf/nightly.conf b/nightly/conf/nightly.conf
index afba9f092..e3b5b3856 100644
--- a/nightly/conf/nightly.conf
+++ b/nightly/conf/nightly.conf
@@ -3,34 +3,34 @@
 ABT_DETAILS="x86_64"
 ABT_JOBS=5
 ABT_KERNELS="  \
-5.10.8         \
+5.10.10        \
 5.9.16-nc      \
 5.8.18-nc      \
 5.7.19-nc      \
 5.6.19-nc      \
 5.5.19-nc      \
-5.4.90-nc      \
+5.4.92-nc      \
 5.3.18-nc      \
 5.2.21-nc      \
 5.1.21-nc      \
 5.0.21-nc      \
 4.20.17-nc     \
-4.19.168-nc    \
+4.19.170-nc    \
 4.18.20-nc     \
 4.17.19-nc     \
 4.16.18-nc     \
 4.15.18-nc     \
-4.14.216-nc    \
+4.14.217-nc    \
 4.13.16-nc     \
 4.12.14-nc     \
 4.11.12-nc     \
 4.10.17-nc     \
-4.9.252-nc     \
+4.9.253-nc     \
 4.8.17-nc      \
 4.7.10-nc      \
 4.6.7-nc       \
 4.5.7-nc       \
-4.4.252-nc     \
+4.4.253-nc     \
 4.3.6-nc       \
 4.2.8-nc       \
 4.1.52-nc      \

From 5a8db0e00f1f4cad42a3423330c2f2aab5b0fa21 Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bvanassche@acm.org>
Date: Sun, 24 Jan 2021 03:59:03 +0000
Subject: [PATCH 2/2] README.performance: Add to repository

git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@9338 d57e44dd-8a1f-0410-8b47-8ef2f437770f
---
 README.performance | 67 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 README.performance

diff --git a/README.performance b/README.performance
new file mode 100644
index 000000000..7a41d64dc
--- /dev/null
+++ b/README.performance
@@ -0,0 +1,67 @@
+SCST Performance
+================
+
+A question that is asked often is how to tune performance. This means how to
+improve the IOPS and/or bandwidth measured at the initiator side. In this
+README it is explained how to optimize storage performance.
+
+Local storage
+-------------
+Start with measuring the performance of the local block device(s). IOPS can be
+measured e.g. as follows:
+
+    fio --ioengine=libaio --rw=randread --ioscheduler=none --numjobs=$(nproc) \
+    --runtime=60 --group_reporting=1 --gtod_reduce=1 --norandommap \
+    --thread --buffered=0 --iodepth=256 --iodepth_batch=128 --bs=4k \
+    --name=bdev --filename=/dev/...
+
+The bandwidth supported by a block device can be measured by increasing the
+block size to a larger value in the above command, e.g. --bs=1M.
+
+Storage network
+---------------
+Start with measuring the network bandwidth using your favorite tool, e.g.
+netperf for non-RDMA networks or ib_write_bw for RDMA networks.
+
+Next, add a nullio LUN to SCST, e.g. by adding the following in /etc/scst.conf:
+
+    HANDLER vdisk_nullio {
+        DEVICE disk09 {
+            blocksize 4096
+            size_mb   256
+        }
+    }
+
+    TARGET_DRIVER ... {
+        TARGET ... {
+	    LUN ... disk09
+	}
+    }
+
+After a nullio LUN has been added, verify that this LUN is visible at the
+initiator side. If it is not visible at the initiator side, consider
+rescanning LUNs or disconnecting and reconnecting the initiator system to the
+SCST server.
+
+Once the nullio LUN is visible at the initiator side, measure IOPS and
+bandwidth. The bandwidth should be close to the network bandwidth. When using
+the Linux iSCSI initiator this may require configuring multiple iSCSI sessions
+and activating multipathd on top of the multiple iSCSI sessions. The sequence
+for logging in with iSCSI and activating multiple iSCSI sessions is as follows:
+
+    iscsiadm -m iface -I iface2 -o new
+    iscsiadm -m iface -I iface2 -o update -n iface.initiatorname -v ${iqn2}
+    iscsiadm -m discovery -t st -p ${scst_ip_address}
+    iscsiadm -m discovery -t st -p ${scst_ip_address} -I iface2
+    iscsiadm -m node -p ${scst_ip_address} -l
+    iscsiadm -m node -p ${scst_ip_address} -I iface2 -l
+
+SCST Configuration
+------------------
+If the number of IOPS measured at the initiator side is significantly lower
+than the minimum of the IOPS supported by the local storage and the storage
+network, further tuning is required. Look up in /proc/interrupts which CPU
+cores process the most network and storage interrupts and configure the SCST
+kernel threads such that these run on other CPU cores than those that process
+the most interrupts by configuring the cpu_mask attribute. More information
+about the SCST cpu_mask sysfs attribute is available in the SCST README.