1 /* chrt.c - Get/set real-time (scheduling) attributes 2 * 3 * Copyright 2016 The Android Open Source Project 4 5 USE_CHRT(NEWTOY(chrt, "mp#bfiorR[!bfior]", TOYFLAG_USR|TOYFLAG_SBIN)) 6 7 config CHRT 8 bool "chrt" 9 default n 10 help 11 usage: chrt [-m] [-p PID] [POLICY PRIO] [COMMAND [ARGS...]] 12 13 Get/set a process' real-time (scheduling) attributes. 14 15 -p Apply to given pid 16 -R Set SCHED_RESET_ON_FORK 17 -m Show min/max priorities available 18 19 Policies: 20 -b SCHED_BATCH -f SCHED_FIFO -i SCHED_IDLE 21 -o SCHED_OTHER -r SCHED_RR 22 */ 23 24 #define FOR_chrt 25 #include "toys.h" 26 27 #include <linux/sched.h> 28 29 GLOBALS( 30 long pid; 31 ) 32 33 static char *policy_name(int policy) { 34 char *policy_names[] = { "SCHED_OTHER", "SCHED_FIFO", "SCHED_RR", 35 "SCHED_BATCH", "4", "SCHED_IDLE", "SCHED_DEADLINE" }; 36 37 return policy < ARRAY_LEN(policy_names) ? policy_names[policy] : "???"; 38 } 39 40 void chrt_main(void) 41 { 42 int policy = SCHED_RR; 43 struct sched_param p; 44 45 // Show min/maxes? 46 if (toys.optflags&FLAG_m) { 47 for (policy = SCHED_OTHER; policy <= SCHED_IDLE; ++policy) 48 if (policy != 4) // There's an unused hole in the priorities. 49 printf("%s min/max priority\t: %d/%d\n", policy_name(policy), 50 sched_get_priority_min(policy), sched_get_priority_max(policy)); 51 return; 52 } 53 54 // If we have a pid but no command or policy, we're just querying. 55 if (TT.pid && !*(toys.optargs+1) && 56 !(toys.optflags&(FLAG_b|FLAG_f|FLAG_i|FLAG_o|FLAG_r))) { 57 policy = sched_getscheduler(TT.pid); 58 if (policy == -1) perror_exit("sched_getscheduler"); 59 policy &= ~SCHED_RESET_ON_FORK; 60 printf("pid %ld's current scheduling policy: %s\n", 61 TT.pid, policy_name(policy)); 62 63 if (sched_getparam(TT.pid, &p)) perror_exit("sched_getparam"); 64 printf("pid %ld's current scheduling priority: %d\n", 65 TT.pid, p.sched_priority); 66 67 return; 68 } 69 70 // Did we get a meaningful combination of arguments? 71 if (!*toys.optargs) help_exit("missing priority"); 72 if (TT.pid && *(toys.optargs+1)) help_exit("-p and command"); 73 if (!TT.pid && !*(toys.optargs+1)) help_exit("missing command"); 74 75 // Translate into policy and priority. 76 if (toys.optflags&FLAG_b) policy = SCHED_BATCH; 77 else if (toys.optflags&FLAG_f) policy = SCHED_FIFO; 78 else if (toys.optflags&FLAG_i) policy = SCHED_IDLE; 79 else if (toys.optflags&FLAG_o) policy = SCHED_OTHER; 80 81 if (toys.optflags&FLAG_R) policy |= SCHED_RESET_ON_FORK; 82 83 p.sched_priority = atolx_range(*toys.optargs, sched_get_priority_min(policy), 84 sched_get_priority_max(policy)); 85 86 if (sched_setscheduler(TT.pid, policy, &p)) perror_exit("sched_setscheduler"); 87 88 if (*(toys.optargs+1)) { 89 toys.stacktop = 0; 90 xexec(++toys.optargs); 91 } 92 } 93
