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 <arturo@xxxxxxxxxxxxx>
---
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 <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)
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");
--
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