=================== Performance Testing

Performance subtests

network

• netperf (linux and windows)
• ntttcp (windows)

block

• iozone (linux)
• iozone (windows) (iozone has its own result analysis module)
• iometer (windows) (not push upstream)
• ffsb (linux)
• qemu_iotests (host)
• fio (linux)

Environment setup

Autotest already supports prepare environment for performance testing, guest/host need to be reboot for some configuration. setup script

Autotest supports to numa pining. Assign "numanode=-1" in tests.cfg, then vcpu threads/vhost_net threads/VM memory will be pined to last numa node. If you want to pin other processes to numa node, you can use numctl and taskset.

::

memory: $ numactl -m $n $cmdline cpu: $ taskset $node_mask $thread_id

The following content is manual guide.

::

1.First level pinning would be to use numa pinning when starting the guest. e.g. $ numactl -c 1 -m 1 qemu-kvm -smp 2 -m 4G <> (pinning guest memory and cpus to numa-node 1)

2.For a single instance test, it would suggest trying a one to one mapping of vcpu to pyhsical core. e.g. get guest vcpu threads id $ taskset -p 40 $vcpus1 #(pinning vcpu1 thread to pyshical cpu #6 ) $ taskset -p 80 $vcpus2 #(pinning vcpu2 thread to physical cpu #7 )

3.To pin vhost on host. get vhost PID and then use taskset to pin it on the same soket. e.g $ taskset -p 20 $vhost #(pinning vcpu2 thread to physical cpu #5 )

4.In guest,pin the IRQ to one core and the netperf to another.

1. make sure irqbalance is off - $ service irqbalance stop
2. find the interrupts - $ cat /proc/interrupts
3. find the affinity mask for the interrupt(s) - $ cat /proc/irq/<irq#>/smp_affinity
4. change the value to match the proper core.make sure the vlaue is cpu mask. e.g. pin the IRQ to first core. $ echo 01>/proc/irq/$virti0-input/sm{p}_{a}ffinity$ echo 01>/proc/irq/$virti0-output/sm{p}_{a}ffinity5)pinthenetservertoanothercore.e.g.$ taskset -p 02 netserver

5.For host to guest scenario. to get maximum performance. make sure to run netperf on different cores on the same numa node as the guest. e.g. $ numactl -m 1 netperf -T 4 (pinning netperf to physical cpu #4)

Execute testing

• Submit jobs in Autotest server, only execute netperf.guset_exhost for three times.

tests.cfg:

::

only netperf.guest_exhost variants: - repeat1: - repeat2: - repeat3:

vbr0 has a static ip: 192.168.100.16

bridge=vbr0

virbr0 is created by libvirtd, guest nic2 get ip by dhcp

bridge_nic2 = virbr0

guest nic1 static ip

ip_nic1 = 192.168.100.21

external host static ip:

client = 192.168.100.15

Result files:

::

$ cd /usr/local/autotest/results/8-debug_user/192.168.122.1/ $ find .|grep RHS kvm.repeat1.r61.virtio_blk.smp2.virtio_net.RHEL.6.1.x86_64.netperf.exhost_guest/results/netperf-result.RHS kvm.repeat2.r61.virtio_blk.smp2.virtio_net.RHEL.6.1.x86_64.netperf.exhost_guest/results/netperf-result.RHS kvm.repeat3.r61.virtio_blk.smp2.virtio_net.RHEL.6.1.x86_64.netperf.exhost_guest/results/netperf-result.RHS

• Submit same job in another env (different packages) with same configuration

Result files:

::

$ cd /usr/local/autotest/results/9-debug_user/192.168.122.1/ $ find .|grep RHS kvm.repeat1.r61.virtio_blk.smp2.virtio_net.RHEL.6.1.x86_64.netperf.exhost_guest/results/netperf-result.RHS kvm.repeat2.r61.virtio_blk.smp2.virtio_net.RHEL.6.1.x86_64.netperf.exhost_guest/results/netperf-result.RHS kvm.repeat3.r61.virtio_blk.smp2.virtio_net.RHEL.6.1.x86_64.netperf.exhost_guest/results/netperf-result.RHS

Analysis result

Config file: perf.conf

.. code-block:: cfg

[ntttcp] result_file_pattern = .*.RHS ignore_col = 1 avg_update =

[netperf] result_file_pattern = .*.RHS ignore_col = 2 avg_update = 4,2,3|14,5,12|15,6,13

[iozone] result_file_pattern =

Execute regression.py to compare two results:

::

login autotest server $ cd /usr/local/autotest/client/tools $ python regression.py netperf /usr/local/autotest/results/8-debug_user/192.168.122.1/ /usr/local/autotest/results/9-debug_user/192.168.122.1/

T-test:

• scipy: http://www.scipy.org/
• t-test: http://en.wikipedia.org/wiki/Student's_t-test
• Two python modules (scipy and numpy) are needed.
• Script to install numpy/scipy on rhel6 automatically: https://github.com/kongove/misc/blob/master/scripts/install-numpy-scipy.sh

Unpaired T-test is used to compare two samples, user can check p-value to know if regression bug exists. If the difference of two samples is considered to be not statistically significant(p <= 0.05), it will add a '+' or '-' before p-value. ('+': avg_sample1 < avg_sample2, '-': avg_sample1 > avg_sample2)

• - only over 95% confidence results will be added "+/-" in "Significance" part.
• + for cpu-usage means regression, "+" for throughput means improvement."

Regression results

• Every Avg line represents the average value based on $n\ast repetitionsofthesametest,andthefollowingSDlinerepresentstheStandardDeviationbetweenthe\ast$n repetitions.
• The Standard deviation is displayed as a percentage of the average.
• The significance of the differences between the two averages is calculated using unpaired T-test that takes into account the SD of the averages.
• The paired t-test is computed for the averages of same category.
• only over 95% confidence results will be added "+/-" in "Significance" part. "+" for cpu-usage means regression, "+" for throughput means improvement.

Highlight HTML result

• green/red --> good/bad
• Significance is larger than 0.95 --> green
• dark green/red --> important (eg: cpu)
• light green/red --> other
• test time
• version (only when diff)
• other: repeat time, title
• user light green/red to highlight small (< %5) DIFF
• highlight Significance with same color in one raw
• add doc link to result file, and describe color in doc

netperf.avg.html

• Raw data that the averages are based on.