Re: [PATCH] pktgen: add a new sample script for 40G and above link testing

On Fri, 2017-08-25 at 11:19 +0200, Jesper Dangaard Brouer wrote:

(please don't use BCC on the netdev list, replies might miss the list in cc)

Comments inlined below:

On Fri, 25 Aug 2017 10:24:30 +0800 Robert Hoo [off-list ref] wrote:

quoted

From: Robert Ho <redacted>

It's hard to benchmark 40G+ network bandwidth using ordinary
tools like iperf, netperf. I then tried with pktgen multiqueue sample
scripts, but still cannot reach line rate.

The pktgen_sample02_multiqueue.sh does not use burst or skb_cloning.
Thus, the performance will suffer.

See the samples that use the burst feature:
  pktgen_sample03_burst_single_flow.sh
  pktgen_sample05_flow_per_thread.sh

With the pktgen "burst" feature, I can easily generate 40G.  Generating
100G is also possible, but often you will hit some HW limits before the
pktgen limit.  I experienced hitting both (1) PCIe Gen3 x8 limit, and (2)
memory bandwidth limit.

Thanks Jesper for review. Sorry for late reply, I do this part time.

I just tried 'pktgen_sample03_burst_single_flow.sh' and 'pktgen_sample05_flow_per_thread.sh'
cmd:
	./pktgen_sample05_flow_per_thread.sh -i ens801 -s 1500 -m 3c:fd:fe:9d:6f:f0 -t 2 -v -x -d 192.168.0.107
	./pktgen_sample03_burst_single_flow.sh -i ens801 -s 1500 -m 3c:fd:fe:9d:6f:f0 -t 2 -v -x -d 192.168.0.107

indeed, they can achieve nearly 40G. (though still slightly less than my 
script). pktgen_sample03 and pktgen_sample05 can approximately achieve 38xxxMb/sec ~ 39xxxMb/sec;
my script can achieve 40xxxMb/sec ~ 41xxxMb/sec. (threads >= 2)

So a general question: is it still necessary to continue my sample06_numa_awared_queue_irq_affinity work? as sample03
and sample05 already approximately achieved 40G line rate.

quoted

I then derived this NUMA awared irq affinity sample script from
multi-queue sample one, successfully benchmarked 40G link. I think this can
also be useful for 100G reference, though I haven't got device to test.

Okay, so your issue was really related to NUMA irq affinity.  I do feel
that IRQ tuning lives outside the realm of the pktgen scripts, but
looking closer at your script, I it doesn't look like you change the
IRQ setting which is good.  

Sorry I don't quite understand above. I changed the irq affinities.
See "echo $thread > /proc/irq/${irq_array[$i]}/smp_affinity_list".
You would not like me to change it? I can restore them to original at the end
of the script.

You introduce some helper functions take makes it possible to extract
NUMA information in the shell script code, really cool.  I would like
to see these functions being integrated into the function.sh file.

Yes, it is doable, if you maintainer think so.

quoted

This script simply does:
Detect $DEV's NUMA node belonging.
Bind each thread (processor from that NUMA node) with each $DEV queue's
irq affinity, 1:1 mapping.
How many '-t' threads input determines how many queues will be
utilized.

Tested with Intel XL710 NIC with Cisco 3172 switch.

It would be even slightly better if the irqbalance service is turned
off outside.

Yes, if you don't turn-off (kill) irqbalance it will move around the
IRQs behind your back...

Yes; while the experiment result turns out it affects just very little.

quoted

Referrences:
https://people.netfilter.org/hawk/presentations/LCA2015/net_stack_challenges_100G_LCA2015.pdf
http://www.intel.cn/content/dam/www/public/us/en/documents/reference-guides/xl710-x710-performance-tuning-linux-guide.pdf

Signed-off-by: Robert Hoo <redacted>
---
 ...tgen_sample06_numa_awared_queue_irq_affinity.sh | 132 +++++++++++++++++++++
 1 file changed, 132 insertions(+)
 create mode 100755 samples/pktgen/pktgen_sample06_numa_awared_queue_irq_affinity.sh

diff --git a/samples/pktgen/pktgen_sample06_numa_awared_queue_irq_affinity.sh b/samples/pktgen/pktgen_sample06_numa_awared_queue_irq_affinity.sh
new file mode 100755
index 0000000..f0ee25c
--- /dev/null
+++ b/samples/pktgen/pktgen_sample06_numa_awared_queue_irq_affinity.sh

@@ -0,0 +1,132 @@
+#!/bin/bash
+#
+# Multiqueue: Using pktgen threads for sending on multiple CPUs
+#  * adding devices to kernel threads which are in the same NUMA node
+#  * bound devices queue's irq affinity to the threads, 1:1 mapping
+#  * notice the naming scheme for keeping device names unique
+#  * nameing scheme: dev@thread_number
+#  * flow variation via random UDP source port
+#
+basedir=`dirname $0`
+source ${basedir}/functions.sh
+root_check_run_with_sudo "$@"
+#
+# Required param: -i dev in $DEV
+source ${basedir}/parameters.sh
+
+get_iface_node()
+{
+	echo `cat /sys/class/net/$1/device/numa_node`

Here you could use the following shell trick to avoid using "cat":

 echo $(</sys/class/net/$1/device/numa_node)

Thanks for teaching. Indeed this is more concise.

It looks like you don't handle the case of -1, which indicate non-NUMA
system.  You need to use something like::

get_iface_node()
{
    local node=$(</sys/class/net/$1/device/numa_node)
    if [[ $node == -1 ]]; then
	echo 0
    else
	echo $node
    fi
}

Yes, I can amend in v2.

quoted

+}
+
+get_iface_irqs()
+{
+	local IFACE=$1
+	local queues="${IFACE}-.*TxRx"
+
+	irqs=$(grep "$queues" /proc/interrupts | cut -f1 -d:)
+	[ -z "$irqs" ] && irqs=$(grep $IFACE /proc/interrupts | cut -f1 -d:)
+	[ -z "$irqs" ] && irqs=$(for i in `ls -Ux /sys/class/net/$IFACE/device/msi_irqs` ;\
+		do grep "$i:.*TxRx" /proc/interrupts | grep -v fdir | cut -f 1 -d : ;\
+	    done)

Nice that you handle all these different methods.  I personally look
in /proc/irq/*/$IFACE*/../smp_affinity_list , like (copy-paste):

echo " --- Align IRQs ---"
# I've named my NICs ixgbe1 + ixgbe2
for F in /proc/irq/*/ixgbe*-TxRx-*/../smp_affinity_list; do
   # Extract irqname e.g. "ixgbe2-TxRx-2"
   irqname=$(basename $(dirname $(dirname $F))) ;
   # Substring pattern removal
   hwq_nr=${irqname#*-*-}
   echo $hwq_nr > $F
   #grep . -H $F;
done
grep -H . /proc/irq/*/ixgbe*/../smp_affinity_list

Maybe I should switch to use:
   /sys/class/net/$IFACE/device/msi_irqs/*
 

quoted

+	[ -z "$irqs" ] && echo "Error: Could not find interrupts for $IFACE"

In the error case you should let the script die.  There is a helper
function for this called "err" (where first arg is the exitcode, which
is useful to detect the reason your script failed).

Yes, I noticed that helper function and changed some of my original "echo Error"s;
this is a missing in my code clear/tidy work. I can amend in v2.

quoted

+	echo $irqs
+}

quoted

+get_node_cpus()
+{
+	local node=$1
+	local node_cpu_list
+	local node_cpu_range_list=`cut -f1- -d, --output-delimiter=" " \
+			/sys/devices/system/node/node$node/cpulist`
+
+	for cpu_range in $node_cpu_range_list
+	do
+		node_cpu_list="$node_cpu_list "`seq -s " " ${cpu_range//-/ }`
+	done
+
+	echo $node_cpu_list
+}
+
+
+# Base Config
+DELAY="0"        # Zero means max speed
+COUNT="20000000"   # Zero means indefinitely
+[ -z "$CLONE_SKB" ] && CLONE_SKB="0"
+
+# Flow variation random source port between min and max
+UDP_MIN=9
+UDP_MAX=109
+
+node=`get_iface_node $DEV`
+irq_array=(`get_iface_irqs $DEV`)
+cpu_array=(`get_node_cpus $node`)

Nice trick to generate an array.

quoted

+
+[ $THREADS -gt ${#irq_array[*]} -o $THREADS -gt ${#cpu_array[*]}  ] && \
+	err 1 "Thread number $THREADS exceeds: min (${#irq_array[*]},${#cpu_array[*]})"
+
+# (example of setting default params in your script)
+if [ -z "$DEST_IP" ]; then
+    [ -z "$IP6" ] && DEST_IP="198.18.0.42" || DEST_IP="FD00::1"
+fi
+[ -z "$DST_MAC" ] && DST_MAC="90:e2:ba:ff:ff:ff"
+
+# General cleanup everything since last run
+pg_ctrl "reset"
+
+# Threads are specified with parameter -t value in $THREADS
+for ((i = 0; i < $THREADS; i++)); do
+    # The device name is extended with @name, using thread number to
+    # make then unique, but any name will do.
+    # Set the queue's irq affinity to this $thread (processor)
+    thread=${cpu_array[$i]}
+    dev=${DEV}@${thread}
+    echo $thread > /proc/irq/${irq_array[$i]}/smp_affinity_list
+    echo "irq ${irq_array[$i]} is set affinity to `cat /proc/irq/${irq_array[$i]}/smp_affinity_list`"
+
+    # Add remove all other devices and add_device $dev to thread
+    pg_thread $thread "rem_device_all"
+    pg_thread $thread "add_device" $dev
+
+    # select queue and bind the queue and $dev in 1:1 relationship
+    queue_num=$i
+    echo "queue number is $queue_num"
+    pg_set $dev "queue_map_min $queue_num"
+    pg_set $dev "queue_map_max $queue_num"
+
+    # Notice config queue to map to cpu (mirrors smp_processor_id())
+    # It is beneficial to map IRQ /proc/irq/*/smp_affinity 1:1 to CPU number
+    pg_set $dev "flag QUEUE_MAP_CPU"
+
+    # Base config of dev
+    pg_set $dev "count $COUNT"
+    pg_set $dev "clone_skb $CLONE_SKB"
+    pg_set $dev "pkt_size $PKT_SIZE"
+    pg_set $dev "delay $DELAY"
+
+    # Flag example disabling timestamping
+    pg_set $dev "flag NO_TIMESTAMP"
+
+    # Destination
+    pg_set $dev "dst_mac $DST_MAC"
+    pg_set $dev "dst$IP6 $DEST_IP"
+
+    # Setup random UDP port src range
+    pg_set $dev "flag UDPSRC_RND"
+    pg_set $dev "udp_src_min $UDP_MIN"
+    pg_set $dev "udp_src_max $UDP_MAX"
+done
+
+# start_run
+echo "Running... ctrl^C to stop" >&2
+pg_ctrl "start"
+echo "Done" >&2
+
+# Print results
+for ((i = 0; i < $THREADS; i++)); do
+    thread=${cpu_array[$i]}
+    dev=${DEV}@${thread}
+    echo "Device: $dev"
+    cat /proc/net/pktgen/$dev | grep -A2 "Result:"
+done