Hi Thomas, On Thu, Mar 21, 2013 at 10:52 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote: > Each architecture implements its own cpu_idle() code, which is more or > less the same on all architectures (plus/minus a few bugs and a few > missing extra functionalities, instrumentation ...). That also forces > everyone who is interested in idle related features to add new > functionality to every architecture. What a waste. I noticed there are still prototypes for cpu_idle() in include/linux/cpu.h and include/linux/smp.h, so I ran a full "git grep -w cpu_idle", which suggested a few more places that needs updates: Documentation/s390/Debugging390.txt:0001b304 T cpu_idle Documentation/s390/Debugging390.txt:is cpu_idle+0x66 ( quiet the cpu is asleep, don't wake it ) Documentation/scheduler/sched-arch.txt:Your cpu_idle routines need to obey the following rules: Documentation/scheduler/sched-arch.txt:3. When cpu_idle finds (need_resched() == 'true'), it should call Documentation/trace/events-power.txt:cpu_idle "state=%lu cpu_id=%lu" Documentation/trace/ftrace.txt: <idle>-0 [002] .N.1 21169.031484: rcu_idle_exit <-cpu_idle Documentation/trace/ftrace.txt: => cpu_idle Documentation/trace/ftrace.txt: <idle>-0 3.N.1 11us : rcu_idle_exit <-cpu_idle Documentation/trace/ftrace.txt: <idle>-0 3.N.1 11us : tick_nohz_idle_exit <-cpu_idle Documentation/trace/ftrace.txt: <idle>-0 3.N.1 25us : sub_preempt_count <-cpu_idle Documentation/trace/ftrace.txt: <idle>-0 3.N.. 25us : schedule <-cpu_idle Documentation/trace/ftrace.txt: <idle>-0 2.N.2 3us : cpu_idle: state=4294967295 cpu_id=2 Documentation/virtual/uml/UserModeLinux-HOWTO.txt: #3 0x100a5508 in cpu_idle () at process_kern.c:471 arch/arm/Kconfig: This option adds a write barrier to the cpu_idle loop so that, arch/cris/arch-v10/drivers/gpio.c: * from cpu_idle() in kernel/process.c arch/cris/arch-v10/drivers/gpio.c: * The check in cpu_idle() reduces latency from ~15 ms to ~6 ms arch/cris/arch-v32/drivers/mach-fs/gpio.c: * from cpu_idle() in kernel/process.c arch/cris/arch-v32/drivers/mach-fs/gpio.c: * The check in cpu_idle() reduces latency from ~15 ms to ~6 ms arch/mips/kernel/smtc.c: printk("Dangling IXMT in cpu_idle()\n"); arch/powerpc/kernel/irq.c: * in cpu_idle() will properly re-enable everything. arch/sparc/kernel/leon_pmc.c:/* leon_pmc.c: LEON Power-down cpu_idle() handler arch/sparc/kernel/smp_32.c: printk("CPU[%d]: Returns from cpu_idle!\n", smp_processor_id()); arch/sparc/kernel/smp_64.c: printk("CPU[%d]: Returns from cpu_idle!\n", smp_processor_id()); arch/tile/include/asm/thread_info.h:/* Enable interrupts racelessly and nap forever: helper for cpu_idle(). */ drivers/acpi/processor_driver.c: * Set flag to delay cpu_idle/throttling initialization include/linux/cpu.h:void cpu_idle(void); include/linux/smp.h:extern void cpu_idle(void); include/trace/events/power.h:DEFINE_EVENT(cpu, cpu_idle, init/main.c: * cpu_idle. init/main.c: /* Call into cpu_idle with preempt disabled */ init/main.c: * fragile until we cpu_idle() for the first time. kernel/trace/power-traces.c:EXPORT_TRACEPOINT_SYMBOL_GPL(cpu_idle); tools/perf/builtin-timechart.c: * Mapping all these "power:cpu_idle" strings to the tracepoint tools/perf/builtin-timechart.c: if (strcmp(event_str, "power:cpu_idle") == 0) { tools/perf/builtin-timechart.c: "-e", "power:cpu_idle", tools/perf/builtin-timechart.c: if (!is_valid_tracepoint("power:cpu_idle") && tools/perf/builtin-top.c: "cpu_idle", Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html