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-rw-r--r--toys/other/chrt.c81
1 files changed, 81 insertions, 0 deletions
diff --git a/toys/other/chrt.c b/toys/other/chrt.c
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+++ b/toys/other/chrt.c
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+/* chrt.c - Get/set real-time (scheduling) attributes
+ *
+ * Copyright 2016 The Android Open Source Project
+ *
+ * Note: -ibrfo flags sorted to match SCHED positions for highest_bit()
+
+USE_CHRT(NEWTOY(chrt, "^mp#<0iRbrfo[!ibrfo]", TOYFLAG_USR|TOYFLAG_SBIN))
+
+config CHRT
+ bool "chrt"
+ default y
+ help
+ usage: chrt [-Rmofrbi] {-p PID [PRIORITY] | [PRIORITY COMMAND...]}
+
+ Get/set a process' real-time scheduling policy and priority.
+
+ -p Set/query given pid (instead of running COMMAND)
+ -R Set SCHED_RESET_ON_FORK
+ -m Show min/max priorities available
+
+ Set policy (default -r):
+
+ -o SCHED_OTHER -f SCHED_FIFO -r SCHED_RR
+ -b SCHED_BATCH -i SCHED_IDLE
+*/
+
+#define FOR_chrt
+#include "toys.h"
+
+GLOBALS(
+ long pid;
+)
+
+char *polnames[] = {
+ "SCHED_OTHER", "SCHED_FIFO", "SCHED_RR", "SCHED_BATCH", 0, "SCHED_IDLE",
+ "SCHED_DEADLINE"
+};
+
+void chrt_main(void)
+{
+ int pol, pri;
+
+ // Show min/maxes?
+ if (toys.optflags&FLAG_m) {
+ for (pol = 0; pol<ARRAY_LEN(polnames); pol++) if (polnames[pol])
+ printf("%s min/max priority\t: %d/%d\n", polnames[pol],
+ sched_get_priority_min(pol), sched_get_priority_max(pol));
+
+ return;
+ }
+
+ // Query when -p without priority.
+ if (toys.optflags==FLAG_p && !*toys.optargs) {
+ char *s = "???", *R = "";
+
+ if (-1==(pol = sched_getscheduler(TT.pid))) perror_exit("pid %ld", TT.pid);
+ if (pol & SCHED_RESET_ON_FORK) R = "|SCHED_RESET_ON_FORK";
+ if ((pol &= ~SCHED_RESET_ON_FORK)<ARRAY_LEN(polnames)) s = polnames[pol];
+ printf("pid %ld's current scheduling policy: %s%s\n", TT.pid, s, R);
+
+ if (sched_getparam(TT.pid, (void *)&pri)) perror_exit("sched_getparam");
+ printf("pid %ld's current scheduling priority: %d\n", TT.pid, pri);
+
+ return;
+ }
+
+ if (!*toys.optargs) help_exit("no PRIORITY");
+ if (!toys.optargs[1] == !(toys.optflags&FLAG_p))
+ help_exit("need 1 of -p or COMMAND");
+
+ // Set policy and priority
+ if (-1==(pol = highest_bit(toys.optflags&0x2f))) pol = SCHED_RR;
+ pri = atolx_range(*toys.optargs, sched_get_priority_min(pol),
+ sched_get_priority_max(pol));
+ if (toys.optflags&FLAG_R) pol |= SCHED_RESET_ON_FORK;
+
+ if (sched_setscheduler(TT.pid, pol, (void *)&pri))
+ perror_exit("sched_setscheduler");
+
+ if (*(toys.optargs+1)) xexec(toys.optargs+1);
+}