Rainer Gerhards wrote:
> I just committed the functionality:
>
> http://git.adiscon.com/?p=rsyslog.git;a=commitdiff;h=cc8237736d11b54a3d6089d8
> 36da7ccb6972a29c
There is a serious flaw there. The pthread_setschedparam() function is
being called by the main thread before other threads are created, so all
threads will inherit the scheduling parameters, which we don't want. That
call has to be moved from willRun() function to the rcvMainLoop() which is
being executed by a new thread so it will afect the UDP thread only. You
can check this with:
ps -eLo "cmd lwp policy rtprio"
I'm attaching a patch which does that, against rsyslog 5.6.2. (After
applying you need to call autoreconf). It also has improved validation.
Note that the allowed scheduling priority range is OS specific, so the
code shouldn't expect that it will be non-negative.
I think that the better way to implement this feature would be to add
pthread_attr_t * as an argument to the willRun() functions in order to
allow them to change the thread properties. Scheduling properties can be
set with pthread_attr_setschedpolicy() and pthread_attr_setschedparam(),
for example.
> Note that I am far from being an autotools expert, so I would appreciate if
> you could provide proper configure checks. I did only a very rough test of
> the functionality.
Included in the patch.
--
.-. .-. Yes, I am an agent of Satan, but my duties are largely
(_ \ / _) ceremonial.
|
| [email protected]
--- configure.ac.orig 2010-12-17 14:58:45.000000000 +0100
+++ configure.ac 2010-12-21 15:24:42.000000000 +0100
@@ -269,6 +269,36 @@
)
fi
+AC_CHECK_FUNCS(
+ [pthread_setschedparam],
+ [
+ rsyslog_have_pthread_setschedparam=yes
+ ],
+ [
+ rsyslog_have_pthread_setschedparam=no
+ ]
+)
+AC_CHECK_HEADERS(
+ [sched.h],
+ [
+ rsyslog_have_sched_h=yes
+ ],
+ [
+ rsyslog_have_sched_h=no
+ ]
+)
+if test "$rsyslog_have_pthread_setschedparam" = "yes" -a "$rsyslog_have_sched_h" = "yes"; then
+ save_LIBS=$LIBS
+ LIBS=
+ AC_SEARCH_LIBS(sched_get_priority_max, rt)
+ if test "x$ac_cv_search" != "xno"; then
+ AC_CHECK_FUNCS(sched_get_priority_max)
+ fi
+ IMUDP_LIBS=$LIBS
+ AC_SUBST(IMUDP_LIBS)
+ LIBS=$save_LIBS
+fi
+
# klog
AC_ARG_ENABLE(klog,
--- plugins/imudp/Makefile.am.orig 2010-12-17 15:02:14.000000000 +0100
+++ plugins/imudp/Makefile.am 2010-12-17 15:02:33.000000000 +0100
@@ -3,4 +3,4 @@
imudp_la_SOURCES = imudp.c
imudp_la_CPPFLAGS = -I$(top_srcdir) $(PTHREADS_CFLAGS) $(RSRT_CFLAGS)
imudp_la_LDFLAGS = -module -avoid-version
-imudp_la_LIBADD =
+imudp_la_LIBADD = $(IMUDP_LIBS)
--- plugins/imudp/imudp.c.orig 2010-12-15 16:06:56.000000000 +0100
+++ plugins/imudp/imudp.c 2010-12-27 17:48:17.000000000 +0100
@@ -35,6 +35,9 @@
#if HAVE_SYS_EPOLL_H
# include <sys/epoll.h>
#endif
+#ifdef HAVE_SCHED_H
+# include <sched.h>
+#endif
#include "rsyslog.h"
#include "dirty.h"
#include "net.h"
@@ -78,12 +81,103 @@
* termination if we can not get it. -- rgerhards, 2007-12-27
*/
static prop_t *pInputName = NULL; /* our inputName currently is always "imudp", and this will hold it */
+static uchar *pszSchedPolicy = NULL; /* scheduling policy string */
+static int iSchedPolicy; /* scheduling policy as SCHED_xxx */
+static int iSchedPrio; /* scheduling priority */
+static int seen_iSchedPrio = 0; /* have we seen scheduling priority in the config file? */
static ruleset_t *pBindRuleset = NULL; /* ruleset to bind listener to (use system default if unspecified) */
#define TIME_REQUERY_DFLT 2
static int iTimeRequery = TIME_REQUERY_DFLT;/* how often is time to be queried inside tight recv loop? 0=always */
/* config settings */
+static rsRetVal check_scheduling_priority(int report_error)
+{
+ DEFiRet;
+
+#ifdef HAVE_SCHED_GET_PRIORITY_MAX
+ if (iSchedPrio < sched_get_priority_min(iSchedPolicy) ||
+ iSchedPrio > sched_get_priority_max(iSchedPolicy)) {
+ if (report_error)
+ errmsg.LogError(errno, NO_ERRCODE,
+ "imudp: scheduling priority %d out of range (%d - %d)"
+ " for scheduling policy '%s' - ignoring settings",
+ iSchedPrio,
+ sched_get_priority_min(iSchedPolicy),
+ sched_get_priority_max(iSchedPolicy),
+ pszSchedPolicy);
+ ABORT_FINALIZE(RS_RET_VALIDATION_RUN);
+ }
+#endif
+
+finalize_it:
+ RETiRet;
+}
+
+/* Set scheduling priority in the supplied variable (will be iSchedPrio)
+ * and record that we have seen the directive (in seen_iSchedPrio).
+ */
+static rsRetVal set_scheduling_priority(void *pVal, int value)
+{
+ DEFiRet;
+
+ if (seen_iSchedPrio) {
+ errmsg.LogError(0, NO_ERRCODE, "directive already seen");
+ ABORT_FINALIZE(RS_RET_VALIDATION_RUN);
+ }
+ *(int *)pVal = value;
+ seen_iSchedPrio = 1;
+ if (pszSchedPolicy != NULL)
+ CHKiRet(check_scheduling_priority(1));
+
+finalize_it:
+ RETiRet;
+}
+
+/* Set scheduling policy in iSchedPolicy */
+static rsRetVal set_scheduling_policy(void *pVal, uchar *pNewVal)
+{
+ int have_sched_policy = 0;
+ DEFiRet;
+
+ if (pszSchedPolicy != NULL) {
+ errmsg.LogError(0, NO_ERRCODE, "directive already seen");
+ ABORT_FINALIZE(RS_RET_VALIDATION_RUN);
+ }
+ *((uchar**)pVal) = pNewVal; /* pVal is pszSchedPolicy */
+ if (0) { /* trick to use conditional compilation */
+#ifdef SCHED_FIFO
+ } else if (!strcasecmp((char*)pszSchedPolicy, "fifo")) {
+ iSchedPolicy = SCHED_FIFO;
+ have_sched_policy = 1;
+#endif
+#ifdef SCHED_RR
+ } else if (!strcasecmp((char*)pszSchedPolicy, "rr")) {
+ iSchedPolicy = SCHED_RR;
+ have_sched_policy = 1;
+#endif
+#ifdef SCHED_OTHER
+ } else if (!strcasecmp((char*)pszSchedPolicy, "other")) {
+ iSchedPolicy = SCHED_OTHER;
+ have_sched_policy = 1;
+#endif
+ } else {
+ errmsg.LogError(errno, NO_ERRCODE,
+ "imudp: invalid scheduling policy '%s' "
+ "- ignoring setting", pszSchedPolicy);
+ }
+ if (have_sched_policy == 0) {
+ free(pszSchedPolicy);
+ pszSchedPolicy = NULL;
+ ABORT_FINALIZE(RS_RET_VALIDATION_RUN);
+ }
+ if (seen_iSchedPrio)
+ CHKiRet(check_scheduling_priority(1));
+
+finalize_it:
+ RETiRet;
+}
+
/* This function is called when a new listener shall be added. It takes
* the configured parameters, tries to bind the socket and, if that
@@ -294,6 +388,41 @@
RETiRet;
}
+static void set_thread_schedparam(void)
+{
+ struct sched_param sparam;
+
+ if (pszSchedPolicy != NULL && seen_iSchedPrio == 0) {
+ errmsg.LogError(0, NO_ERRCODE,
+ "imudp: scheduling policy set, but without priority - ignoring settings");
+ } else if (pszSchedPolicy == NULL && seen_iSchedPrio != 0) {
+ errmsg.LogError(0, NO_ERRCODE,
+ "imudp: scheduling priority set, but without policy - ignoring settings");
+ } else if (pszSchedPolicy != NULL && seen_iSchedPrio != 0 &&
+ check_scheduling_priority(0) == 0) {
+#ifndef HAVE_PTHREAD_SETSCHEDPARAM
+ errmsg.LogError(0, NO_ERRCODE,
+ "imudp: cannot set thread scheduling policy, "
+ "pthread_setschedparam() not available");
+#else
+ int err;
+
+ memset(&sparam, 0, sizeof sparam);
+ sparam.sched_priority = iSchedPrio;
+ dbgprintf("imudp trying to set sched policy to '%s', prio %d\n",
+ pszSchedPolicy, iSchedPrio);
+ err = pthread_setschedparam(pthread_self(), iSchedPolicy, &sparam);
+ if (err != 0) {
+ errmsg.LogError(err, NO_ERRCODE, "imudp: pthread_setschedparam() failed");
+ }
+#endif
+ }
+
+ if (pszSchedPolicy != NULL) {
+ free(pszSchedPolicy);
+ pszSchedPolicy = NULL;
+ }
+}
/* This function implements the main reception loop. Depending on the environment,
* we either use the traditional (but slower) select() or the Linux-specific epoll()
@@ -317,6 +446,7 @@
/* start "name caching" algo by making sure the previous system indicator
* is invalidated.
*/
+ set_thread_schedparam();
bIsPermitted = 0;
memset(&frominetPrev, 0, sizeof(frominetPrev));
@@ -384,6 +514,7 @@
/* start "name caching" algo by making sure the previous system indicator
* is invalidated.
*/
+ set_thread_schedparam();
bIsPermitted = 0;
memset(&frominetPrev, 0, sizeof(frominetPrev));
DBGPRINTF("imudp uses select()\n");
@@ -539,6 +670,10 @@
addListner, NULL, STD_LOADABLE_MODULE_ID));
CHKiRet(omsdRegCFSLineHdlr((uchar *)"udpserveraddress", 0, eCmdHdlrGetWord,
NULL, &pszBindAddr, STD_LOADABLE_MODULE_ID));
+ CHKiRet(omsdRegCFSLineHdlr((uchar *)"imudpschedulingpolicy", 0, eCmdHdlrGetWord,
+ &set_scheduling_policy, &pszSchedPolicy, STD_LOADABLE_MODULE_ID));
+ CHKiRet(omsdRegCFSLineHdlr((uchar *)"imudpschedulingpriority", 0, eCmdHdlrInt,
+ &set_scheduling_priority, &iSchedPrio, STD_LOADABLE_MODULE_ID));
CHKiRet(omsdRegCFSLineHdlr((uchar *)"udpservertimerequery", 0, eCmdHdlrInt,
NULL, &iTimeRequery, STD_LOADABLE_MODULE_ID));
CHKiRet(omsdRegCFSLineHdlr((uchar *)"resetconfigvariables", 1, eCmdHdlrCustomHandler,
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