chrt: add support for SCHED_DEADLINE

This patch introduces

	-d, --deadline
	-T, --sched-runtime
	-D, --sched-deadline
	-P, --sched-period

command line options. The functionality is available only for Linux with
sched_setattr() [kernel >=3.14]

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/schedutils/chrt.1 b/schedutils/chrt.1
index c7da4ebe7df8e00fc4ab853b0f6ba3680c149256..ad52b128d328f9c04371ba2763cf0d97648d4390 100644 (file)
--- a/schedutils/chrt.1
+++ b/schedutils/chrt.1
@@ -41,6 +41,7 @@ or runs \fIcommand\fR with the given attributes.  Both the policy (one of
 .BR SCHED_FIFO ,
 .BR SCHED_RR ,
 .BR SCHED_BATCH ,
+.BR SCHED_DEADLINE ,
 or
 .BR SCHED_IDLE )
 and the priority can be set and retrieved.
@@ -49,7 +50,9 @@ The
 .BR SCHED_BATCH
 policy is supported since Linux 2.6.16.  The
 .BR SCHED_IDLE
-policy is supported since Linux 2.6.23.
+policy is supported since Linux 2.6.23.  The
+.BR SCHED_DEADLINE
+policy is supported since Linux 3.14.
 .PP
 The
 .BR SCHED_RESET_ON_FORK
@@ -66,6 +69,19 @@ Set scheduling policy to
 .B SCHED_BATCH
 (Linux-specific). The priority argument has to be set to zero.
 .TP
+.BR -d ,\  --deadline
+Set policy scheduling policy to
+.BR SCHED_DEADLINE
+(Linux-specific). The priority argument has to be set to zero. See also \fB\-\-sched\-runtime\fR,
+\fB\-\-sched\-deadline\fR and \fB\-\-sched\-period\fR. The relation between
+the options required by kernel is runtime <= deadline <= period.
+.B chrt
+copies \fIperiod\fR to \fIdeadline\fR if \fB\-\-sched\-deadline\fR is no specified and
+\fIdeadline\fR to \fIruntime\fR if \fB\-\-sched\-runtime\fR is no specified. It means at least
+\fB\-\-sched\-period\fR has to be specified. See
+.BR sched (7)
+for more details.
+.TP
 .BR -f ,\  --fifo
 Set scheduling policy to
 .BR SCHED_FIFO .
@@ -101,6 +117,15 @@ When policy is not defined the
 .B SCHED_RR
 is used as default.
 .TP
+\fB\-T\fR, \fB\-\-sched\-runtime\fR \fInanoseconds\fR
+Specifies runtime parameter for SCHED_DEADLINE policy (Linux-specific).
+.TP
+\fB\-P\fR, \fB\-\-sched\-period\fR \fInanoseconds\fR
+Specifies period parameter for SCHED_DEADLINE policy (Linux-specific).
+.TP
+\fB\-D\fR, \fB\-\-sched\-deadline\fR \fInanoseconds\fR
+Specifies deadline parameter for SCHED_DEADLINE policy (Linux-specific).
+.TP
 .BR -v ,\  --verbose
 Show status information.
 .TP
@@ -143,6 +168,7 @@ Linux default scheduling policy is
 .BR taskset (1),
 .BR nice (1),
 .BR renice (1)
+.BR sched (7)
 .sp
 See
 .BR sched_setscheduler (2)

diff --git a/schedutils/chrt.c b/schedutils/chrt.c
index ee08821f4036a975f62d9a679eed3ec71097288f..e468f4a6d25ed352df6f10b2e649de5418a40987 100644 (file)
--- a/schedutils/chrt.c
+++ b/schedutils/chrt.c
@@ -52,6 +52,7 @@
 #define SCHED_RESET_ON_FORK 0x40000000
 #endif
 
+
 #if defined (__linux__) && !defined(HAVE_SCHED_SETATTR)
 # include <sys/syscall.h>
 #endif
@@ -85,7 +86,15 @@ static int sched_getattr(pid_t pid, struct sched_attr *attr, unsigned int size,
 {
        return syscall(SYS_sched_getattr, pid, attr, size, flags);
 }
-#endif /* !HAVE_SCHED_SETATTR */
+#endif
+
+/* the SCHED_DEADLINE is supported since Linux 3.14
+ * commit id aab03e05e8f7e26f51dee792beddcb5cca9215a5
+ * -- sched_setattr() is required for this policy!
+ */
+#if defined (__linux__) && !defined(SCHED_DEADLINE) && defined(HAVE_SCHED_SETATTR)
+# define SCHED_DEADLINE 6
+#endif
 
 
 /* control struct */
@@ -94,6 +103,10 @@ struct chrt_ctl {
        int     policy;                         /* SCHED_* */
        int     priority;
 
+       uint64_t runtime;                       /* --sched-* options */
+       uint64_t deadline;
+       uint64_t period;
+
        unsigned int all_tasks : 1,             /* all threads of the PID */
                     reset_on_fork : 1,         /* SCHED_RESET_ON_FORK */
                     altered : 1,               /* sched_set**() used */
@@ -116,16 +129,19 @@ static void __attribute__((__noreturn__)) show_usage(int rc)
        fputs(USAGE_SEPARATOR, out);
        fputs(_("Policy options:\n"), out);
        fputs(_(" -b, --batch          set policy to SCHED_BATCH\n"), out);
+       fputs(_(" -d, --deadline       set policy to SCHED_DEADLINE\n"), out);
        fputs(_(" -f, --fifo           set policy to SCHED_FIFO\n"), out);
        fputs(_(" -i, --idle           set policy to SCHED_IDLE\n"), out);
        fputs(_(" -o, --other          set policy to SCHED_OTHER\n"), out);
        fputs(_(" -r, --rr             set policy to SCHED_RR (default)\n"), out);
 
-#ifdef SCHED_RESET_ON_FORK
        fputs(USAGE_SEPARATOR, out);
-       fputs(_("Scheduling flag:\n"), out);
-       fputs(_(" -R, --reset-on-fork  set SCHED_RESET_ON_FORK for FIFO or RR\n"), out);
-#endif
+       fputs(_("Scheduling options:\n"), out);
+       fputs(_(" -R, --reset-on-fork       set SCHED_RESET_ON_FORK for FIFO or RR\n"), out);
+       fputs(_(" -T, --sched-runtime <ns>  runtime parameter for DEADLINE\n"), out);
+       fputs(_(" -P, --sched-period <ns>   period parameter for DEADLINE\n"), out);
+       fputs(_(" -D, --sched-deadline <ns> deadline parameter for DEADLINE\n"), out);
+
        fputs(USAGE_SEPARATOR, out);
        fputs(_("Other options:\n"), out);
        fputs(_(" -a, --all-tasks      operate on all the tasks (threads) for a given pid\n"), out);
@@ -188,6 +204,11 @@ static void show_sched_pid_info(struct chrt_ctl *ctl, pid_t pid)
        case SCHED_BATCH:
                printf("SCHED_BATCH\n");
                break;
+#endif
+#ifdef SCHED_DEADLINE
+       case SCHED_DEADLINE:
+               printf("SCHED_DEADLINE\n");
+               break;
 #endif
        default:
                warnx(_("unknown scheduling policy"));
@@ -234,6 +255,9 @@ static void show_min_max(void)
 #endif
 #ifdef SCHED_IDLE
                SCHED_IDLE,
+#endif
+#ifdef SCHED_DEADLINE
+               SCHED_DEADLINE,
 #endif
        };
        const char *names[] = {
@@ -245,6 +269,9 @@ static void show_min_max(void)
 #endif
 #ifdef SCHED_IDLE
                "IDLE",
+#endif
+#ifdef SCHED_DEADLINE
+               "DEADLINE",
 #endif
        };
 
@@ -276,9 +303,13 @@ static int set_sched_one(struct chrt_ctl *ctl, pid_t pid)
 #else /* !HAVE_SCHED_SETATTR */
 static int set_sched_one(struct chrt_ctl *ctl, pid_t pid)
 {
+       /* use main() to check if the setting makes sense */
        struct sched_attr sa = {
                .sched_policy   = ctl->policy,
-               .sched_priority = ctl->priority
+               .sched_priority = ctl->priority,
+               .sched_runtime = ctl->runtime,
+               .sched_period = ctl->period,
+               .sched_deadline = ctl->deadline
        };
 # ifdef SCHED_RESET_ON_FORK
        if (ctl->reset_on_fork)
@@ -315,19 +346,23 @@ int main(int argc, char **argv)
        int c;
 
        static const struct option longopts[] = {
-               { "all-tasks",  0, NULL, 'a' },
-               { "batch",      0, NULL, 'b' },
-               { "fifo",       0, NULL, 'f' },
-               { "idle",       0, NULL, 'i' },
-               { "pid",        0, NULL, 'p' },
-               { "help",       0, NULL, 'h' },
-               { "max",        0, NULL, 'm' },
-               { "other",      0, NULL, 'o' },
-               { "rr",         0, NULL, 'r' },
-               { "reset-on-fork", 0, NULL, 'R' },
-               { "verbose",    0, NULL, 'v' },
-               { "version",    0, NULL, 'V' },
-               { NULL,         0, NULL, 0 }
+               { "all-tasks",  no_argument, NULL, 'a' },
+               { "batch",      no_argument, NULL, 'b' },
+               { "deadline",   no_argument, NULL, 'd' },
+               { "fifo",       no_argument, NULL, 'f' },
+               { "idle",       no_argument, NULL, 'i' },
+               { "pid",        no_argument, NULL, 'p' },
+               { "help",       no_argument, NULL, 'h' },
+               { "max",        no_argument, NULL, 'm' },
+               { "other",      no_argument, NULL, 'o' },
+               { "rr",         no_argument, NULL, 'r' },
+               { "sched-runtime",  required_argument, NULL, 'T' },
+               { "sched-period",   required_argument, NULL, 'P' },
+               { "sched-deadline", required_argument, NULL, 'D' },
+               { "reset-on-fork",  no_argument,       NULL, 'R' },
+               { "verbose",    no_argument, NULL, 'v' },
+               { "version",    no_argument, NULL, 'V' },
+               { NULL,         no_argument, NULL, 0 }
        };
 
        setlocale(LC_ALL, "");
@@ -335,7 +370,7 @@ int main(int argc, char **argv)
        textdomain(PACKAGE);
        atexit(close_stdout);
 
-       while((c = getopt_long(argc, argv, "+abfiphmoRrvV", longopts, NULL)) != -1)
+       while((c = getopt_long(argc, argv, "+abdDfiphmoPTrRvV", longopts, NULL)) != -1)
        {
                int ret = EXIT_FAILURE;
 
@@ -346,6 +381,12 @@ int main(int argc, char **argv)
                case 'b':
 #ifdef SCHED_BATCH
                        ctl->policy = SCHED_BATCH;
+#endif
+                       break;
+
+               case 'd':
+#ifdef SCHED_DEADLINE
+                       ctl->policy = SCHED_DEADLINE;
 #endif
                        break;
                case 'f':
@@ -375,6 +416,15 @@ int main(int argc, char **argv)
                case 'v':
                        ctl->verbose = 1;
                        break;
+               case 'T':
+                       ctl->runtime = strtou64_or_err(optarg, _("invalid runtime argument"));
+                       break;
+               case 'P':
+                       ctl->period = strtou64_or_err(optarg, _("invalid period argument"));
+                       break;
+               case 'D':
+                       ctl->deadline = strtou64_or_err(optarg, _("invalid deadline argument"));
+                       break;
                case 'V':
                        printf(UTIL_LINUX_VERSION);
                        return EXIT_SUCCESS;
@@ -400,10 +450,28 @@ int main(int argc, char **argv)
        ctl->priority = strtos32_or_err(argv[optind], _("invalid priority argument"));
 
 #ifdef SCHED_RESET_ON_FORK
-       if (ctl->reset_on_fork)
-               if (ctl->policy != SCHED_FIFO && ctl->policy != SCHED_RR)
-                       errx(EXIT_FAILURE, _("SCHED_RESET_ON_FORK flag is supported for "
-                                            "SCHED_FIFO and SCHED_RR policies only"));
+       if (ctl->reset_on_fork && ctl->policy != SCHED_FIFO && ctl->policy != SCHED_RR)
+               errx(EXIT_FAILURE, _("--reset-on-fork option is supported for "
+                                    "SCHED_FIFO and SCHED_RR policies only"));
+#endif
+#ifdef SCHED_DEADLINE
+       if ((ctl->runtime || ctl->deadline || ctl->period) && ctl->policy != SCHED_DEADLINE)
+               errx(EXIT_FAILURE, _("--sched-{runtime,deadline,period} options "
+                                    "are supported for SCHED_DEADLINE only"));
+       if (ctl->policy == SCHED_DEADLINE) {
+               /* The basic rule is runtime <= deadline <= period, so we can
+                * make deadline and runtime optional on command line. Note we
+                * don't check any values or set any defaults, it's kernel
+                * responsibility.
+                */
+               if (ctl->deadline == 0)
+                       ctl->deadline = ctl->period;
+               if (ctl->runtime == 0)
+                       ctl->runtime = ctl->deadline;
+       }
+#else
+       if (ctl->runtime || ctl->deadline || ctl->period)
+               errx(EXIT_FAILURE, _("SCHED_DEADLINE is unsupported"));
 #endif
        if (ctl->pid == -1)
                ctl->pid = 0;