From 10a85d467da4e045fbc754489dfcdd8c097ed44e Mon Sep 17 00:00:00 2001 From: Arturo Borrero Gonzalez Date: Thu, 7 Sep 2017 13:36:53 +0200 Subject: 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 --- src/ulogd.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) 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 #include #include +#include #include #include #ifdef DEBUG @@ -1395,6 +1396,19 @@ static void signal_handler_task(int signal) deliver_signal_pluginstances(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(); ulogd_log(ULOGD_INFO, "initialization finished, entering main loop\n"); -- cgit v1.2.3