Loading Documentation/block/ioprio.txt 0 → 100644 +176 −0 Original line number Original line Diff line number Diff line Block io priorities =================== Intro ----- With the introduction of cfq v3 (aka cfq-ts or time sliced cfq), basic io priorities is supported for reads on files. This enables users to io nice processes or process groups, similar to what has been possible to cpu scheduling for ages. This document mainly details the current possibilites with cfq, other io schedulers do not support io priorities so far. Scheduling classes ------------------ CFQ implements three generic scheduling classes that determine how io is served for a process. IOPRIO_CLASS_RT: This is the realtime io class. This scheduling class is given higher priority than any other in the system, processes from this class are given first access to the disk every time. Thus it needs to be used with some care, one io RT process can starve the entire system. Within the RT class, there are 8 levels of class data that determine exactly how much time this process needs the disk for on each service. In the future this might change to be more directly mappable to performance, by passing in a wanted data rate instead. IOPRIO_CLASS_BE: This is the best-effort scheduling class, which is the default for any process that hasn't set a specific io priority. The class data determines how much io bandwidth the process will get, it's directly mappable to the cpu nice levels just more coarsely implemented. 0 is the highest BE prio level, 7 is the lowest. The mapping between cpu nice level and io nice level is determined as: io_nice = (cpu_nice + 20) / 5. IOPRIO_CLASS_IDLE: This is the idle scheduling class, processes running at this level only get io time when no one else needs the disk. The idle class has no class data, since it doesn't really apply here. Tools ----- See below for a sample ionice tool. Usage: # ionice -c<class> -n<level> -p<pid> If pid isn't given, the current process is assumed. IO priority settings are inherited on fork, so you can use ionice to start the process at a given level: # ionice -c2 -n0 /bin/ls will run ls at the best-effort scheduling class at the highest priority. For a running process, you can give the pid instead: # ionice -c1 -n2 -p100 will change pid 100 to run at the realtime scheduling class, at priority 2. ---> snip ionice.c tool <--- #include <stdio.h> #include <stdlib.h> #include <errno.h> #include <getopt.h> #include <unistd.h> #include <sys/ptrace.h> #include <asm/unistd.h> extern int sys_ioprio_set(int, int, int); extern int sys_ioprio_get(int, int); #if defined(__i386__) #define __NR_ioprio_set 289 #define __NR_ioprio_get 290 #elif defined(__ppc__) #define __NR_ioprio_set 273 #define __NR_ioprio_get 274 #elif defined(__x86_64__) #define __NR_ioprio_set 251 #define __NR_ioprio_get 252 #elif defined(__ia64__) #define __NR_ioprio_set 1274 #define __NR_ioprio_get 1275 #else #error "Unsupported arch" #endif _syscall3(int, ioprio_set, int, which, int, who, int, ioprio); _syscall2(int, ioprio_get, int, which, int, who); enum { IOPRIO_CLASS_NONE, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE, }; enum { IOPRIO_WHO_PROCESS = 1, IOPRIO_WHO_PGRP, IOPRIO_WHO_USER, }; #define IOPRIO_CLASS_SHIFT 13 const char *to_prio[] = { "none", "realtime", "best-effort", "idle", }; int main(int argc, char *argv[]) { int ioprio = 4, set = 0, ioprio_class = IOPRIO_CLASS_BE; int c, pid = 0; while ((c = getopt(argc, argv, "+n:c:p:")) != EOF) { switch (c) { case 'n': ioprio = strtol(optarg, NULL, 10); set = 1; break; case 'c': ioprio_class = strtol(optarg, NULL, 10); set = 1; break; case 'p': pid = strtol(optarg, NULL, 10); break; } } switch (ioprio_class) { case IOPRIO_CLASS_NONE: ioprio_class = IOPRIO_CLASS_BE; break; case IOPRIO_CLASS_RT: case IOPRIO_CLASS_BE: break; case IOPRIO_CLASS_IDLE: ioprio = 7; break; default: printf("bad prio class %d\n", ioprio_class); return 1; } if (!set) { if (!pid && argv[optind]) pid = strtol(argv[optind], NULL, 10); ioprio = ioprio_get(IOPRIO_WHO_PROCESS, pid); printf("pid=%d, %d\n", pid, ioprio); if (ioprio == -1) perror("ioprio_get"); else { ioprio_class = ioprio >> IOPRIO_CLASS_SHIFT; ioprio = ioprio & 0xff; printf("%s: prio %d\n", to_prio[ioprio_class], ioprio); } } else { if (ioprio_set(IOPRIO_WHO_PROCESS, pid, ioprio | ioprio_class << IOPRIO_CLASS_SHIFT) == -1) { perror("ioprio_set"); return 1; } if (argv[optind]) execvp(argv[optind], &argv[optind]); } return 0; } ---> snip ionice.c tool <--- March 11 2005, Jens Axboe <axboe@suse.de> Documentation/cciss.txt +1 −0 Original line number Original line Diff line number Diff line Loading @@ -17,6 +17,7 @@ This driver is known to work with the following cards: * SA P600 * SA P600 * SA P800 * SA P800 * SA E400 * SA E400 * SA E300 If nodes are not already created in the /dev/cciss directory, run as root: If nodes are not already created in the /dev/cciss directory, run as root: Loading Documentation/kernel-parameters.txt +1 −1 Original line number Original line Diff line number Diff line Loading @@ -1115,7 +1115,7 @@ running once the system is up. See Documentation/ramdisk.txt. See Documentation/ramdisk.txt. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to probe for (bare|imps|exps). probe for (bare|imps|exps|lifebook|any). psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports per second. per second. psmouse.resetafter= psmouse.resetafter= Loading MAINTAINERS +1 −1 Original line number Original line Diff line number Diff line Loading @@ -1156,7 +1156,7 @@ S: Maintained INFINIBAND SUBSYSTEM INFINIBAND SUBSYSTEM P: Roland Dreier P: Roland Dreier M: roland@topspin.com M: rolandd@cisco.com P: Sean Hefty P: Sean Hefty M: mshefty@ichips.intel.com M: mshefty@ichips.intel.com P: Hal Rosenstock P: Hal Rosenstock Loading arch/arm/kernel/process.c +4 −1 Original line number Original line Diff line number Diff line Loading @@ -32,6 +32,7 @@ #include <asm/leds.h> #include <asm/leds.h> #include <asm/processor.h> #include <asm/processor.h> #include <asm/uaccess.h> #include <asm/uaccess.h> #include <asm/mach/time.h> extern const char *processor_modes[]; extern const char *processor_modes[]; extern void setup_mm_for_reboot(char mode); extern void setup_mm_for_reboot(char mode); Loading Loading @@ -85,8 +86,10 @@ EXPORT_SYMBOL(pm_power_off); void default_idle(void) void default_idle(void) { { local_irq_disable(); local_irq_disable(); if (!need_resched() && !hlt_counter) if (!need_resched() && !hlt_counter) { timer_dyn_reprogram(); arch_idle(); arch_idle(); } local_irq_enable(); local_irq_enable(); } } Loading Loading
Documentation/block/ioprio.txt 0 → 100644 +176 −0 Original line number Original line Diff line number Diff line Block io priorities =================== Intro ----- With the introduction of cfq v3 (aka cfq-ts or time sliced cfq), basic io priorities is supported for reads on files. This enables users to io nice processes or process groups, similar to what has been possible to cpu scheduling for ages. This document mainly details the current possibilites with cfq, other io schedulers do not support io priorities so far. Scheduling classes ------------------ CFQ implements three generic scheduling classes that determine how io is served for a process. IOPRIO_CLASS_RT: This is the realtime io class. This scheduling class is given higher priority than any other in the system, processes from this class are given first access to the disk every time. Thus it needs to be used with some care, one io RT process can starve the entire system. Within the RT class, there are 8 levels of class data that determine exactly how much time this process needs the disk for on each service. In the future this might change to be more directly mappable to performance, by passing in a wanted data rate instead. IOPRIO_CLASS_BE: This is the best-effort scheduling class, which is the default for any process that hasn't set a specific io priority. The class data determines how much io bandwidth the process will get, it's directly mappable to the cpu nice levels just more coarsely implemented. 0 is the highest BE prio level, 7 is the lowest. The mapping between cpu nice level and io nice level is determined as: io_nice = (cpu_nice + 20) / 5. IOPRIO_CLASS_IDLE: This is the idle scheduling class, processes running at this level only get io time when no one else needs the disk. The idle class has no class data, since it doesn't really apply here. Tools ----- See below for a sample ionice tool. Usage: # ionice -c<class> -n<level> -p<pid> If pid isn't given, the current process is assumed. IO priority settings are inherited on fork, so you can use ionice to start the process at a given level: # ionice -c2 -n0 /bin/ls will run ls at the best-effort scheduling class at the highest priority. For a running process, you can give the pid instead: # ionice -c1 -n2 -p100 will change pid 100 to run at the realtime scheduling class, at priority 2. ---> snip ionice.c tool <--- #include <stdio.h> #include <stdlib.h> #include <errno.h> #include <getopt.h> #include <unistd.h> #include <sys/ptrace.h> #include <asm/unistd.h> extern int sys_ioprio_set(int, int, int); extern int sys_ioprio_get(int, int); #if defined(__i386__) #define __NR_ioprio_set 289 #define __NR_ioprio_get 290 #elif defined(__ppc__) #define __NR_ioprio_set 273 #define __NR_ioprio_get 274 #elif defined(__x86_64__) #define __NR_ioprio_set 251 #define __NR_ioprio_get 252 #elif defined(__ia64__) #define __NR_ioprio_set 1274 #define __NR_ioprio_get 1275 #else #error "Unsupported arch" #endif _syscall3(int, ioprio_set, int, which, int, who, int, ioprio); _syscall2(int, ioprio_get, int, which, int, who); enum { IOPRIO_CLASS_NONE, IOPRIO_CLASS_RT, IOPRIO_CLASS_BE, IOPRIO_CLASS_IDLE, }; enum { IOPRIO_WHO_PROCESS = 1, IOPRIO_WHO_PGRP, IOPRIO_WHO_USER, }; #define IOPRIO_CLASS_SHIFT 13 const char *to_prio[] = { "none", "realtime", "best-effort", "idle", }; int main(int argc, char *argv[]) { int ioprio = 4, set = 0, ioprio_class = IOPRIO_CLASS_BE; int c, pid = 0; while ((c = getopt(argc, argv, "+n:c:p:")) != EOF) { switch (c) { case 'n': ioprio = strtol(optarg, NULL, 10); set = 1; break; case 'c': ioprio_class = strtol(optarg, NULL, 10); set = 1; break; case 'p': pid = strtol(optarg, NULL, 10); break; } } switch (ioprio_class) { case IOPRIO_CLASS_NONE: ioprio_class = IOPRIO_CLASS_BE; break; case IOPRIO_CLASS_RT: case IOPRIO_CLASS_BE: break; case IOPRIO_CLASS_IDLE: ioprio = 7; break; default: printf("bad prio class %d\n", ioprio_class); return 1; } if (!set) { if (!pid && argv[optind]) pid = strtol(argv[optind], NULL, 10); ioprio = ioprio_get(IOPRIO_WHO_PROCESS, pid); printf("pid=%d, %d\n", pid, ioprio); if (ioprio == -1) perror("ioprio_get"); else { ioprio_class = ioprio >> IOPRIO_CLASS_SHIFT; ioprio = ioprio & 0xff; printf("%s: prio %d\n", to_prio[ioprio_class], ioprio); } } else { if (ioprio_set(IOPRIO_WHO_PROCESS, pid, ioprio | ioprio_class << IOPRIO_CLASS_SHIFT) == -1) { perror("ioprio_set"); return 1; } if (argv[optind]) execvp(argv[optind], &argv[optind]); } return 0; } ---> snip ionice.c tool <--- March 11 2005, Jens Axboe <axboe@suse.de>
Documentation/cciss.txt +1 −0 Original line number Original line Diff line number Diff line Loading @@ -17,6 +17,7 @@ This driver is known to work with the following cards: * SA P600 * SA P600 * SA P800 * SA P800 * SA E400 * SA E400 * SA E300 If nodes are not already created in the /dev/cciss directory, run as root: If nodes are not already created in the /dev/cciss directory, run as root: Loading
Documentation/kernel-parameters.txt +1 −1 Original line number Original line Diff line number Diff line Loading @@ -1115,7 +1115,7 @@ running once the system is up. See Documentation/ramdisk.txt. See Documentation/ramdisk.txt. psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to psmouse.proto= [HW,MOUSE] Highest PS2 mouse protocol extension to probe for (bare|imps|exps). probe for (bare|imps|exps|lifebook|any). psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports psmouse.rate= [HW,MOUSE] Set desired mouse report rate, in reports per second. per second. psmouse.resetafter= psmouse.resetafter= Loading
MAINTAINERS +1 −1 Original line number Original line Diff line number Diff line Loading @@ -1156,7 +1156,7 @@ S: Maintained INFINIBAND SUBSYSTEM INFINIBAND SUBSYSTEM P: Roland Dreier P: Roland Dreier M: roland@topspin.com M: rolandd@cisco.com P: Sean Hefty P: Sean Hefty M: mshefty@ichips.intel.com M: mshefty@ichips.intel.com P: Hal Rosenstock P: Hal Rosenstock Loading
arch/arm/kernel/process.c +4 −1 Original line number Original line Diff line number Diff line Loading @@ -32,6 +32,7 @@ #include <asm/leds.h> #include <asm/leds.h> #include <asm/processor.h> #include <asm/processor.h> #include <asm/uaccess.h> #include <asm/uaccess.h> #include <asm/mach/time.h> extern const char *processor_modes[]; extern const char *processor_modes[]; extern void setup_mm_for_reboot(char mode); extern void setup_mm_for_reboot(char mode); Loading Loading @@ -85,8 +86,10 @@ EXPORT_SYMBOL(pm_power_off); void default_idle(void) void default_idle(void) { { local_irq_disable(); local_irq_disable(); if (!need_resched() && !hlt_counter) if (!need_resched() && !hlt_counter) { timer_dyn_reprogram(); arch_idle(); arch_idle(); } local_irq_enable(); local_irq_enable(); } } Loading
