trafgen: disable timer slack

linux has default time slack of 50 usec, which means that trafgen
'gap' option is unable to precisely control delays.

Set the process timer slack to the minimum of 1 nsec.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/trafgen.c b/trafgen.c
index 0a645d4..9151b5d 100644
--- a/trafgen.c
+++ b/trafgen.c
@@ -14,6 +14,7 @@
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <sys/fsuid.h>
+#include <sys/prctl.h>
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/wait.h>
@@ -957,6 +958,7 @@ int main(int argc, char **argv)
 		case 't':
 			slow = true;
 			ptr = optarg;
+			prctl(PR_SET_TIMERSLACK, 1UL);
 			gap = strtoul(optarg, NULL, 0);
 
 			for (j = i = strlen(optarg); i > 0; --i) {