* Damien Wyart <damien.wyart@xxxxxxx> wrote: > * Ingo Molnar <mingo@xxxxxxx> [090216 10:50]: > > hm, we need a trace with both abstime and process information included: > > > echo funcgraph-proc > trace_options > > echo funcgraph-abstime > trace_options > > > Also, at 140 msecs the duration is a bit short - could you please make a > > 1-2 seconds capture? You can do that by increasing the number in > > buffer_size_kb 10-fold: > > > echo 14100 > buffer_size_kb > > Ok, I've redone a trace with these options enabled. The file is here: > http://damien.wyart.free.fr/ksoftirqd_pb/trace_tip_2009.02.16_ksoftirqd_pb_abstime_proc.txt.gz ok, here's the new annotated trace: 799.555279 | 1) ksoftir-2324 | | do_softirq() { 799.555279 | 1) ksoftir-2324 | | __do_softirq() { 799.555280 | 1) ksoftir-2324 | | /* #1 softirq pending: 00000100 */ 799.555281 | 1) ksoftir-2324 | | /* #2 softirq pending: 00000000 */ 799.555282 | 1) ksoftir-2324 | | rcu_process_callbacks() { 799.555282 | 1) ksoftir-2324 | | __rcu_process_callbacks() { 799.555283 | 1) ksoftir-2324 | 0.479 us | force_quiescent_state(); 799.555284 | 1) ksoftir-2324 | 1.576 us | } 799.555284 | 1) ksoftir-2324 | | __rcu_process_callbacks() { 799.555285 | 1) ksoftir-2324 | | force_quiescent_state() { 799.555286 | 1) ksoftir-2324 | | cpu_quiet() { 799.555286 | 1) ksoftir-2324 | 0.518 us | _spin_lock_irqsave(); 799.555287 | 1) ksoftir-2324 | 0.506 us | _spin_unlock_irqrestore(); 799.555288 | 1) ksoftir-2324 | 2.563 us | } 799.555289 | 1) ksoftir-2324 | 4.624 us | } 799.555289 | 1) ksoftir-2324 | 7.836 us | } 799.555290 | 1) ksoftir-2324 | 0.495 us | _local_bh_enable(); 799.555291 | 1) ksoftir-2324 | + 11.550 us | } 799.555291 | 1) ksoftir-2324 | + 12.713 us | } 799.555292 | 1) ksoftir-2324 | 0.524 us | _cond_resched(); We do get 0x100 which is 1 << RCU_SOFTIRQ, i.e. the RCU softirq. Paul, this indeed seems to be a CONFIG_TREE_RCU=y bug. What is weird is that RCU_SOFTIRQ gets set again and again - but there's no raise_softirq() calls. Could you please do a two-CPU trace too via: echo 3 > /debug/tracing/tracing_cpumask So that we can see what's happening on the other CPU? Also, could you please apply the debug patch below (or update to the very latest -tip tree), so that we get trace entries of softirq triggers too? Thanks, Ingo --------------> >From 6876d5d56716427f9bbe3af7e4e9c06cb760ae0c Mon Sep 17 00:00:00 2001 From: Ingo Molnar <mingo@xxxxxxx> Date: Mon, 16 Feb 2009 13:23:36 +0100 Subject: [PATCH] softirq: debug #2 Signed-off-by: Ingo Molnar <mingo@xxxxxxx> --- include/linux/interrupt.h | 3 ++- kernel/softirq.c | 7 +++++++ 2 files changed, 9 insertions(+), 1 deletions(-) diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h index e7bcfd7..cc1f529 100644 --- a/include/linux/interrupt.h +++ b/include/linux/interrupt.h @@ -271,7 +271,8 @@ asmlinkage void do_softirq(void); asmlinkage void __do_softirq(void); extern void open_softirq(int nr, void (*action)(struct softirq_action *)); extern void softirq_init(void); -#define __raise_softirq_irqoff(nr) do { or_softirq_pending(1UL << (nr)); } while (0) +#define ___raise_softirq_irqoff(nr) do { or_softirq_pending(1UL << (nr)); } while (0) +extern void __raise_softirq_irqoff(unsigned int nr); extern void raise_softirq_irqoff(unsigned int nr); extern void raise_softirq(unsigned int nr); diff --git a/kernel/softirq.c b/kernel/softirq.c index 110cad0..431cb4f 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -302,6 +302,13 @@ void irq_exit(void) preempt_enable_no_resched(); } +void __raise_softirq_irqoff(unsigned int nr) +{ + ftrace_printk("nr: %d\n", nr); + or_softirq_pending(1UL << nr); +} +EXPORT_SYMBOL_GPL(__raise_softirq_irqoff); + /* * This function must run with irqs disabled! */ -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
