diff options
authorArturo Borrero Gonzalez <>2017-09-07 13:36:53 +0200
committerPablo Neira Ayuso <>2017-09-20 10:53:43 +0200
commit10a85d467da4e045fbc754489dfcdd8c097ed44e (patch)
parentfafa58537a014af5205896b8753a79b6bf1b8f44 (diff)
ulogd: use a RT scheduler by default
Is common that ulogd runs in scenarios where a lot of packets are to be logged. If there are more packets than ulogd can handle, users can start seing log messages like this: ulogd[556]: We are losing events. Please, consider using the clauses \ `netlink_socket_buffer_size' and `netlink_socket_buffer_maxsize' Which means that Netlink buffer overrun have happened. There are several approaches to prevent this situation: * in the ruleset, limit the amount of packet queued for log * in the ruleset, instruct the kernel to use a queue-threshold * from userspace, increment Netlink buffer sizes * from userspace, configure ulogd to run as high priority process The first 3 method can be configured by users at runtime. This patch deals with the last method. SCHED_RR is configured by default, with no associated configuration parameter for users, since I believe this is common enough, and should produce no harm. A similar approach is used in the conntrackd daemon. Signed-off-by: Arturo Borrero Gonzalez <> Acked-by: Eric Leblond <> Signed-off-by: Pablo Neira Ayuso <>
1 files changed, 15 insertions, 0 deletions
diff --git a/src/ulogd.c b/src/ulogd.c
index b85d0ee..684444f 100644
--- a/src/ulogd.c
+++ b/src/ulogd.c
@@ -64,6 +64,7 @@
#include <syslog.h>
#include <sys/time.h>
#include <sys/stat.h>
+#include <sched.h>
#include <ulogd/conffile.h>
#include <ulogd/ulogd.h>
#ifdef DEBUG
@@ -1395,6 +1396,19 @@ static void signal_handler_task(int signal)
+static void set_scheduler(void)
+ struct sched_param schedparam;
+ int sched_type;
+ schedparam.sched_priority = sched_get_priority_max(SCHED_RR);
+ sched_type = SCHED_RR;
+ if (sched_setscheduler(0, sched_type, &schedparam) < 0)
+ fprintf(stderr, "WARNING: scheduler configuration failed:"
+ " %s\n", strerror(errno));
static void print_usage(void)
printf("ulogd Version %s\n", VERSION);
@@ -1589,6 +1603,7 @@ int main(int argc, char* argv[])
signal(SIGALRM, &signal_handler);
signal(SIGUSR1, &signal_handler);
signal(SIGUSR2, &signal_handler);
+ set_scheduler();
"initialization finished, entering main loop\n");