Messages in this thread | | | Date | Tue, 17 Feb 2009 19:20:45 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] tracing/function-graph-tracer: trace the idle tasks |
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* Frederic Weisbecker <fweisbec@gmail.com> wrote:
> When the function graph tracer is activated, it iterates over the task_list > to allocate a stack to store the return addresses. > But the per cpu idle tasks are not iterated by using do_each_thread / while_each_thread. > So we have to iterate on them manually. > > This fixes somes weirdness in the traces and many losses of traces. > Examples on two cpus: > > 0) Xorg-4287 | 2.906 us | } > 0) Xorg-4287 | 3.965 us | } > 0) Xorg-4287 | 5.302 us | } > ------------------------------------------ > 0) Xorg-4287 => <idle>-0 > ------------------------------------------ > > 0) <idle>-0 | 2.861 us | } > 0) <idle>-0 | 0.526 us | set_normalized_timespec(); > 0) <idle>-0 | 7.201 us | } > 0) <idle>-0 | 8.214 us | } > 0) <idle>-0 | | clockevents_program_event() { > 0) <idle>-0 | | lapic_next_event() { > 0) <idle>-0 | 0.510 us | native_apic_mem_write(); > 0) <idle>-0 | 1.546 us | } > 0) <idle>-0 | 2.583 us | } > 0) <idle>-0 | + 12.435 us | } > 0) <idle>-0 | + 13.470 us | } > 0) <idle>-0 | 0.608 us | _spin_unlock_irqrestore(); > 0) <idle>-0 | + 23.270 us | } > 0) <idle>-0 | + 24.336 us | } > 0) <idle>-0 | + 25.417 us | } > 0) <idle>-0 | 0.593 us | _spin_unlock(); > 0) <idle>-0 | + 41.869 us | } > 0) <idle>-0 | + 42.906 us | } > 0) <idle>-0 | + 95.035 us | } > 0) <idle>-0 | 0.540 us | menu_reflect(); > 0) <idle>-0 | ! 100.404 us | } > 0) <idle>-0 | 0.564 us | mce_idle_callback(); > 0) <idle>-0 | | enter_idle() { > 0) <idle>-0 | 0.526 us | mce_idle_callback(); > 0) <idle>-0 | 1.757 us | } > 0) <idle>-0 | | cpuidle_idle_call() { > 0) <idle>-0 | | menu_select() { > 0) <idle>-0 | 0.525 us | pm_qos_requirement(); > 0) <idle>-0 | 0.518 us | tick_nohz_get_sleep_length(); > 0) <idle>-0 | 2.621 us | } > [...] > 1) <idle>-0 | 0.518 us | touch_softlockup_watchdog(); > 1) <idle>-0 | + 14.355 us | } > 1) <idle>-0 | + 22.840 us | } > 1) <idle>-0 | + 25.949 us | } > 1) <idle>-0 | | handle_irq() { > 1) <idle>-0 | 0.511 us | irq_to_desc(); > 1) <idle>-0 | | handle_edge_irq() { > 1) <idle>-0 | 0.638 us | _spin_lock(); > 1) <idle>-0 | | ack_apic_edge() { > 1) <idle>-0 | 0.510 us | irq_to_desc(); > 1) <idle>-0 | | move_native_irq() { > 1) <idle>-0 | 0.510 us | irq_to_desc(); > 1) <idle>-0 | 1.532 us | } > 1) <idle>-0 | 0.511 us | native_apic_mem_write(); > ------------------------------------------ > 1) <idle>-0 => cat-5073 > ------------------------------------------ > > 1) cat-5073 | 3.731 us | } > 1) cat-5073 | | run_local_timers() { > 1) cat-5073 | 0.533 us | hrtimer_run_queues(); > 1) cat-5073 | | raise_softirq() { > 1) cat-5073 | | __raise_softirq_irqoff() { > 1) cat-5073 | | /* nr: 1 */ > 1) cat-5073 | 2.718 us | } > 1) cat-5073 | 3.814 us | } > > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> > --- > kernel/trace/ftrace.c | 6 +++++- > 1 files changed, 5 insertions(+), 1 deletions(-)
Applied to tip:tracing/urgent, thanks Frederic!
Ingo
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