test/vsock: vsock_perf utility

This adds utility to check vsock rx/tx performance.

Usage as sender:
./vsock_perf --sender <cid> --port <port> --bytes <bytes to send>
Usage as receiver:
./vsock_perf --port <port> --rcvlowat <SO_RCVLOWAT>

Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: Arseniy Krasnov

tools/testing/vsock/Makefile

@@ -1,8 +1,9 @@
 # SPDX-License-Identifier: GPL-2.0-only
-all: test
+all: test vsock_perf
 test: vsock_test vsock_diag_test
 vsock_test: vsock_test.o timeout.o control.o util.o
 vsock_diag_test: vsock_diag_test.o timeout.o control.o util.o
+vsock_perf: vsock_perf.o
 
 CFLAGS += -g -O2 -Werror -Wall -I. -I../../include -I../../../usr/include -Wno-pointer-sign -fno-strict-overflow -fno-strict-aliasing -fno-common -MMD -U_FORTIFY_SOURCE -D_GNU_SOURCE
 .PHONY: all test clean

tools/testing/vsock/README

@@ -35,3 +35,37 @@ Invoke test binaries in both directions as follows:
                        --control-port=$GUEST_IP \
                        --control-port=1234 \
                        --peer-cid=3
+
+vsock_perf utility
+-------------------
+'vsock_perf' is a simple tool to measure vsock performance. It works in
+sender/receiver modes: sender connect to peer at the specified port and
+starts data transmission to the receiver. After data processing is done,
+it prints several metrics(see below).
+
+Usage:
+# run as sender
+# connect to CID 2, port 1234, send 1G of data, tx buf size is 1M
+./vsock_perf --sender 2 --port 1234 --bytes 1G --buf-size 1M
+
+Output:
+tx performance: A Gbits/s
+
+Output explanation:
+A is calculated as "number of bits to send" / "time in tx loop"
+
+# run as receiver
+# listen port 1234, rx buf size is 1M, socket buf size is 1G, SO_RCVLOWAT is 64K
+./vsock_perf --port 1234 --buf-size 1M --vsk-size 1G --rcvlowat 64K
+
+Output:
+rx performance: A Gbits/s
+total in 'read()': B sec
+POLLIN wakeups: C
+average in 'read()': D ns
+
+Output explanation:
+A is calculated as "number of received bits" / "time in rx loop".
+B is time, spent in 'read()' system call(excluding 'poll()')
+C is number of 'poll()' wake ups with POLLIN bit set.
+D is B / C, e.g. average amount of time, spent in single 'read()'.