Hello,
Please find below a patch to enable the use of the TimerFD API
to the cyclictest program.
It add the -F option for this, and can be used on either MONOTONIC and REALTIME
clock, in absolute or relative time.
It has been tested on CentOS4 with a custom , 2.6.19-rt15 kernel and on a
Debian Lenny with a -wireless-testing kernel (non-preempt-rt), so far.
(The latest shown a strange behavior : in MONOTONIC / RELATIVE clocking,
sometimes it happen that the minimum delay become negative. In my opinion, it
would mean that the read() syscall returned *before* the required expiration
delay - but it might just be a bug in my code. It does not appear on the
preempt-rt kernel)
Please let me know if you see any obvious mistake. You may include this patch
in the repository at will.
Bye,
obconseil
--
People in the embedded space don't do prototypes. They hack something until it
works, then it's done.
---
Always code as if the person who will maintain your code is a maniac serial
killer that knows where you live
diff --git a/Makefile b/Makefile
index 911b05e..e9491dd 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
VERSION_STRING = 0.50
TARGETS = cyclictest signaltest classic_pi pi_stress hwlatdetect
-FLAGS = -Wall -Wno-nonnull -O2
+FLAGS = -Wall -Wno-nonnull -O2 -DWITH_TIMERFD
LIBS = -lpthread -lrt
DESTDIR ?=
prefix ?= /usr/local
diff --git a/src/cyclictest/cyclictest.c b/src/cyclictest/cyclictest.c
index 2b4dc50..580f140 100644
--- a/src/cyclictest/cyclictest.c
+++ b/src/cyclictest/cyclictest.c
@@ -46,6 +46,43 @@
#define gettid() syscall(__NR_gettid)
#define sigev_notify_thread_id _sigev_un._tid
+#ifdef WITH_TIMERFD
+/*
+ * This were good at the time of 2.6.23-rc7 ...
+ */
+#ifndef __NR_timerfd
+
+#if defined(__x86_64__)
+#define __NR_timerfd_create 283
+#define __NR_timerfd_settime 286
+#define __NR_timerfd_gettime 287
+
+#elif defined(__i386__)
+#define __NR_timerfd_create 322
+#define __NR_timerfd_settime 325
+#define __NR_timerfd_gettime 326
+
+#else
+#error Cannot detect your architecture!
+#endif
+
+#define TFD_TIMER_ABSTIME (1 << 0)
+inline int timerfd_create(int clockid, int flags) {
+ return syscall(__NR_timerfd_create, clockid, flags);
+}
+
+inline int timerfd_settime(int ufc, int flags, const struct itimerspec *utmr,
+ struct itimerspec *otmr) {
+ return syscall(__NR_timerfd_settime, ufc, flags, utmr, otmr);
+}
+
+inline int timerfd_gettime(int ufc, struct itimerspec *otmr) {
+ return syscall(__NR_timerfd_gettime, ufc, otmr);
+}
+#endif
+#endif // timerfd
+
+
#ifdef __UCLIBC__
#define MAKE_PROCESS_CPUCLOCK(pid, clock) \
((~(clockid_t) (pid) << 3) | (clockid_t) (clock))
@@ -74,7 +111,7 @@ static void CPU_ZERO(cpu_set_t *set) { }
extern int clock_nanosleep(clockid_t __clock_id, int __flags,
__const struct timespec *__req,
struct timespec *__rem);
-#endif
+#endif // uclibc
#define USEC_PER_SEC 1000000
#define NSEC_PER_SEC 1000000000
@@ -86,6 +123,7 @@ extern int clock_nanosleep(clockid_t __clock_id, int __flags,
#define MODE_SYS_ITIMER 2
#define MODE_SYS_NANOSLEEP 3
#define MODE_SYS_OFFSET 2
+#define MODE_TIMERFD 4
#define TIMER_RELTIME 0
@@ -553,6 +591,7 @@ parse_time_string(char *val)
* Modes:
* - clock_nanosleep based
* - cyclic timer based
+ * - timerfd based
*
* Clock:
* - CLOCK_MONOTONIC
@@ -574,6 +613,10 @@ void *timerthread(void *param)
struct thread_stat *stat = par->stats;
int stopped = 0;
cpu_set_t mask;
+#ifdef WITH_TIMERFD
+ int timerfd_id = 0;
+ unsigned long long timerfd_data=0;
+#endif
if (par->cpu != -1) {
CPU_ZERO(&mask);
@@ -599,7 +642,13 @@ void *timerthread(void *param)
timer_create(par->clock, &sigev, &timer);
tspec.it_interval = interval;
}
-
+#ifdef WITH_TIMERFD
+ if (par->mode == MODE_TIMERFD) {
+ timerfd_id = timerfd_create(par->clock, 0);
+ if (timerfd_id == -1)
+ fprintf(stderr,"Error : Cannot create the timerfd\n");
+ }
+#endif
memset(&schedp, 0, sizeof(schedp));
schedp.sched_priority = par->prio;
sched_setscheduler(0, par->policy, &schedp);
@@ -615,6 +664,7 @@ void *timerthread(void *param)
stop.tv_sec += duration;
tsnorm(&stop);
}
+
if (par->mode == MODE_CYCLIC) {
if (par->timermode == TIMER_ABSTIME)
tspec.it_value = next;
@@ -632,7 +682,20 @@ void *timerthread(void *param)
itimer.it_interval.tv_usec = interval.tv_nsec / 1000;
setitimer (ITIMER_REAL, &itimer, NULL);
}
-
+#ifdef WITH_TIMERFD
+ if (par->mode == MODE_TIMERFD) {
+ tspec.it_interval.tv_sec = interval.tv_sec;
+ tspec.it_interval.tv_nsec = interval.tv_nsec;
+ if (par->timermode == TIMER_ABSTIME) {
+ tspec.it_value = next;
+ timerfd_settime(timerfd_id,TFD_TIMER_ABSTIME,&tspec,NULL);
+ } else {
+ tspec.it_value.tv_nsec = 0;
+ tspec.it_value.tv_sec = 1;
+ timerfd_settime(timerfd_id,0,&tspec,NULL);
+ }
+ }
+#endif
stat->threadstarted++;
while (!shutdown) {
@@ -656,7 +719,7 @@ void *timerthread(void *param)
clock_gettime(par->clock, &now);
ret = clock_nanosleep(par->clock, TIMER_RELTIME,
&interval, NULL);
- next.tv_sec = now.tv_sec + interval.tv_sec;
+ next.tv_sec = now.tv_sec + interval.tv_sec;
next.tv_nsec = now.tv_nsec + interval.tv_nsec;
tsnorm(&next);
}
@@ -676,9 +739,22 @@ void *timerthread(void *param)
next.tv_nsec = now.tv_nsec + interval.tv_nsec;
tsnorm(&next);
break;
+#ifdef WITH_TIMERFD
+ case MODE_TIMERFD:
+ if (par->timermode == TIMER_ABSTIME) {
+ read(timerfd_id,&timerfd_data,8);
+ } else {
+ clock_gettime(par->clock, &now);
+ timerfd_gettime(timerfd_id,&tspec);
+ read(timerfd_id,&timerfd_data,8);
+ next.tv_sec = now.tv_sec + tspec.it_value.tv_sec;
+ next.tv_nsec = now.tv_nsec + tspec.it_value.tv_nsec;
+ tsnorm(&next);
+ }
+ break;
+#endif
}
clock_gettime(par->clock, &now);
-
if (use_nsecs)
diff = calcdiff_ns(now, next);
else
@@ -734,7 +810,11 @@ out:
itimer.it_interval.tv_usec = 0;
setitimer (ITIMER_REAL, &itimer, NULL);
}
-
+#ifdef WITH_TIMERFD
+ if (par->mode == MODE_TIMERFD) {
+ close(timerfd_id);
+ }
+#endif
/* switch to normal */
schedp.sched_priority = 0;
sched_setscheduler(0, SCHED_OTHER, &schedp);
@@ -775,6 +855,9 @@ static void display_help(int error)
" to modify value to minutes, hours or days\n"
"-E --event event tracing (used with -b)\n"
"-f --ftrace function trace (when -b is active)\n"
+#ifdef WITH_TIMERFD
+ "-F --timerfd Use TimerFD API\n"
+#endif
"-h --histogram=US dump a latency histogram to stdout after the run\n"
" (with same priority about many threads)\n"
" US is the max time to be be tracked in microseconds\n"
@@ -813,6 +896,7 @@ static void display_help(int error)
static int use_nanosleep;
static int timermode = TIMER_ABSTIME;
static int use_system;
+static int use_timerfd;
static int priority;
static int policy = 0;
static int num_threads = 1;
@@ -899,6 +983,9 @@ static void process_options (int argc, char *argv[])
{"distance", required_argument, NULL, 'd'},
{"event", no_argument, NULL, 'E'},
{"ftrace", no_argument, NULL, 'f'},
+#ifdef WITH_TIMERFD
+ {"timerfd",no_argument,NULL,'F'},
+#endif
{"histogram", required_argument, NULL, 'h'},
{"interval", required_argument, NULL, 'i'},
{"irqsoff", no_argument, NULL, 'I'},
@@ -923,7 +1010,7 @@ static void process_options (int argc, char *argv[])
{"traceopt", required_argument, NULL, 'O'},
{NULL, 0, NULL, 0}
};
- int c = getopt_long (argc, argv, "a::b:Bc:Cd:Efh:i:Il:nNo:O:p:Pmqrst::vD:wWTy:",
+ int c = getopt_long (argc, argv, "a::b:Bc:Cd:EfFh:i:Il:nNo:O:p:Pmqrst::vD:wWTy:",
long_options, &option_index);
if (c == -1)
break;
@@ -946,6 +1033,9 @@ static void process_options (int argc, char *argv[])
case 'd': distance = atoi(optarg); break;
case 'E': tracetype = EVENTS; break;
case 'f': ftrace = 1; break;
+#ifdef WITH_TIMERFD
+ case 'F': use_timerfd = MODE_TIMERFD; break;
+#endif
case 'h': histogram = atoi(optarg); break;
case 'i': interval = atoi(optarg); break;
case 'I': tracetype = IRQSOFF; break;
@@ -1207,7 +1297,7 @@ int main(int argc, char **argv)
if (check_timer())
fprintf(stderr, "WARNING: High resolution timers not available\n");
- mode = use_nanosleep + use_system;
+ mode = use_timerfd ? use_timerfd : (use_nanosleep + use_system);
sigemptyset(&sigset);
sigaddset(&sigset, signum);
