From b0d0a09235093cf11fbe83ce502d7079bc255f7e Mon Sep 17 00:00:00 2001
From: Michal Sojka <sojkam1@fel.cvut.cz>
Date: Thu, 22 Sep 2011 04:22:34 +0200
Subject: [PATCH] Speedup cpu-load experiments by stopping hackbench during
 maintenance

---
 gw-tests/lib.sh       |  5 +++--
 latester/Makefile.omk |  3 +++
 latester/latester.c   | 15 +++++++++++++++
 latester/setpgid.c    | 29 +++++++++++++++++++++++++++++
 4 files changed, 50 insertions(+), 2 deletions(-)
 create mode 100644 latester/setpgid.c

diff --git a/gw-tests/lib.sh b/gw-tests/lib.sh
index c5492e8..8cfcf26 100644
--- a/gw-tests/lib.sh
+++ b/gw-tests/lib.sh
@@ -91,9 +91,10 @@ traffic_and_length() {
 }
 
 start_load() {
+    unset LATESTER_CONTROL_HACKBENCH
     case $load in
 	none) ;;
-	cpu) sshgw 'hackbench -g 3 -l 100000' & loadpid=$!;;
+	cpu) export LATESTER_CONTROL_HACKBENCH=$(sshgw 'nohup setpgid hackbench -g 3 -l 100000  >/dev/null & echo $!');;
 	eth) ping -f -s 60000 -q 192.168.2.3 & loadpid=$!;; # TODO: Generate eth load from another computer
 	can) latester -q -d can1 -i 0x7ff & loadpid=$!;;
 	*) error "Unknown load specification: $load"
@@ -103,7 +104,7 @@ start_load() {
 kill_load() {
     case $load in
 	none) ;;
-	cpu) kill $loadpid; sshgw "killall -q hackbench || :";;
+	cpu) sshgw "kill -9 -$LATESTER_CONTROL_HACKBENCH; killall -q -9 hackbench || :";;
 	eth) kill $loadpid;;
 	can) kill $loadpid;;
 	*) error "Unknown load specification: $load"
diff --git a/latester/Makefile.omk b/latester/Makefile.omk
index 0b9029d..0d1e2be 100644
--- a/latester/Makefile.omk
+++ b/latester/Makefile.omk
@@ -8,3 +8,6 @@ INCLUDES = -DSO_RXQ_OVFL=40 \
 	   -DPF_CAN=29 \
 	   -DAF_CAN=PF_CAN
 
+
+bin_PROGRAMS += setpgid
+setpgid_SOURCES = setpgid.c
diff --git a/latester/latester.c b/latester/latester.c
index d09b1ab..30e62f1 100644
--- a/latester/latester.c
+++ b/latester/latester.c
@@ -884,6 +884,13 @@ int main(int argc, const char *argv[])
 		error(1, errno, "pipe fcntl");
 
 	init_ftrace();
+	if (getenv("LATESTER_CONTROL_HACKBENCH")) {
+		char cmd[1000];
+		sprintf(cmd, "ssh -x -a -S $HOME/.ssh/cangw-connection root@192.168.2.3 'kill -CONT -%s'",
+			getenv("LATESTER_CONTROL_HACKBENCH"));
+		printf("Running: %s\n", cmd);
+		system(cmd);
+	}
 
 	pthread_create(&thread, 0, measure_thread, NULL);
 
@@ -933,6 +940,14 @@ int main(int argc, const char *argv[])
 
 	pthread_join(thread, NULL);
 
+	if (getenv("LATESTER_CONTROL_HACKBENCH")) {
+		char cmd[1000];
+		sprintf(cmd, "ssh -x -a -S $HOME/.ssh/cangw-connection root@192.168.2.3 'kill -STOP -%s'",
+			getenv("LATESTER_CONTROL_HACKBENCH"));
+		printf("Running: %s\n", cmd);
+		system(cmd);
+	}
+
 	close(completion_pipe[0]);
 	close(completion_pipe[1]);
 
diff --git a/latester/setpgid.c b/latester/setpgid.c
new file mode 100644
index 0000000..0562302
--- /dev/null
+++ b/latester/setpgid.c
@@ -0,0 +1,29 @@
+#define _XOPEN_SOURCE 500
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+
+int main(int argc, char *argv[])
+{
+	if (argc < 2) {
+		fprintf(stderr, "Usage: %s <command>\n", argv[0]);
+		return 1;
+	}
+	pid_t pid;
+	pid = atol(argv[1]);
+	if (setpgid(0, 0) != 0) {
+		perror("setpgid");
+		return 1;
+	}
+
+	char **newargv = malloc(sizeof(void*)*argc);
+	unsigned i;
+	for (i=1; i<argc; i++)
+		newargv[i-1] = argv[i];
+	newargv[argc-1] = NULL;
+	kill(0, SIGSTOP);
+	execvp(argv[1], newargv);
+	perror("execvp");   /* execve() only returns on error */
+	exit(EXIT_FAILURE);
+}
-- 
2.39.2