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-rw-r--r--toys/pending/chrt.c92
1 files changed, 92 insertions, 0 deletions
diff --git a/toys/pending/chrt.c b/toys/pending/chrt.c
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+/* chrt.c - Get/set real-time (scheduling) attributes
+ *
+ * Copyright 2016 The Android Open Source Project
+
+USE_CHRT(NEWTOY(chrt, "mp#bfiorR[!bfior]", TOYFLAG_USR|TOYFLAG_SBIN))
+
+config CHRT
+ bool "chrt"
+ default y
+ help
+ usage: chrt [-m] [-p PID] [POLICY PRIO] [COMMAND [ARGS...]]
+
+ Get/set a process' real-time (scheduling) attributes.
+
+ -p Apply to given pid
+ -R Set SCHED_RESET_ON_FORK
+ -m Show min/max priorities available
+
+ Policies:
+ -b SCHED_BATCH -f SCHED_FIFO -i SCHED_IDLE
+ -o SCHED_OTHER -r SCHED_RR
+*/
+
+#define FOR_chrt
+#include "toys.h"
+
+#include <linux/sched.h>
+
+GLOBALS(
+ long pid;
+)
+
+static char *policy_name(int policy) {
+ char *policy_names[] = { "SCHED_OTHER", "SCHED_FIFO", "SCHED_RR",
+ "SCHED_BATCH", "4", "SCHED_IDLE", "SCHED_DEADLINE" };
+
+ return policy < ARRAY_LEN(policy_names) ? policy_names[policy] : "???";
+}
+
+void chrt_main(void)
+{
+ int policy = SCHED_RR;
+ struct sched_param p;
+
+ // Show min/maxes?
+ if (toys.optflags&FLAG_m) {
+ for (policy = SCHED_OTHER; policy <= SCHED_IDLE; ++policy)
+ if (policy != 4) // There's an unused hole in the priorities.
+ printf("%s min/max priority\t: %d/%d\n", policy_name(policy),
+ sched_get_priority_min(policy), sched_get_priority_max(policy));
+ return;
+ }
+
+ // If we have a pid but no command or policy, we're just querying.
+ if (TT.pid && !*(toys.optargs+1) &&
+ !(toys.optflags&(FLAG_b|FLAG_f|FLAG_i|FLAG_o|FLAG_r))) {
+ policy = sched_getscheduler(TT.pid);
+ if (policy == -1) perror_exit("sched_getscheduler");
+ policy &= ~SCHED_RESET_ON_FORK;
+ printf("pid %ld's current scheduling policy: %s\n",
+ TT.pid, policy_name(policy));
+
+ if (sched_getparam(TT.pid, &p)) perror_exit("sched_getparam");
+ printf("pid %ld's current scheduling priority: %d\n",
+ TT.pid, p.sched_priority);
+
+ return;
+ }
+
+ // Did we get a meaningful combination of arguments?
+ if (!*toys.optargs) help_exit("missing priority");
+ if (TT.pid && *(toys.optargs+1)) help_exit("-p and command");
+ if (!TT.pid && !*(toys.optargs+1)) help_exit("missing command");
+
+ // Translate into policy and priority.
+ if (toys.optflags&FLAG_b) policy = SCHED_BATCH;
+ else if (toys.optflags&FLAG_f) policy = SCHED_FIFO;
+ else if (toys.optflags&FLAG_i) policy = SCHED_IDLE;
+ else if (toys.optflags&FLAG_o) policy = SCHED_OTHER;
+
+ if (toys.optflags&FLAG_R) policy |= SCHED_RESET_ON_FORK;
+
+ p.sched_priority = atolx_range(*toys.optargs, sched_get_priority_min(policy),
+ sched_get_priority_max(policy));
+
+ if (sched_setscheduler(TT.pid, policy, &p)) perror_exit("sched_setscheduler");
+
+ if (*(toys.optargs+1)) {
+ toys.stacktop = 0;
+ xexec(++toys.optargs);
+ }
+}