Subject: Re: [4.4-rt PATCH] trace: use rcuidle version for preemptoff_hist trace point

* Yang Shi | 2016-02-23 13:23:23 [-0800]:

>I recall the rcuidle version is used by 4.1-rt, but not sure why it is dropped
>in 4.4-rt. It looks such fix is still needed.

I don't recall while I removed it. It was durring v4.1 -> v4.4 port. In
v4.1 we had the idle version only in time_hardirqs_on() + …_off(). You
introduced it also to start_critical_timings() + stop_…(). Is this
required?
In the meantime I bring back the empty macro of
trace_preemptirqsoff_hist_rcuidle() back in -RT sine it breaks compile
latest v4.4.3-RT9

> kernel/trace/trace_irqsoff.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
>diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
>index 36e584f..069942c 100644
>--- a/kernel/trace/trace_irqsoff.c
>+++ b/kernel/trace/trace_irqsoff.c
>@@ -421,13 +421,13 @@ void start_critical_timings(void)
> {
> if (preempt_trace() || irq_trace())
> start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
>- trace_preemptirqsoff_hist(TRACE_START, 1);
>+ trace_preemptirqsoff_hist_rcuidle(TRACE_START, 1);
> }
> EXPORT_SYMBOL_GPL(start_critical_timings);
>
> void stop_critical_timings(void)
> {
>- trace_preemptirqsoff_hist(TRACE_STOP, 0);
>+ trace_preemptirqsoff_hist_rcuidle(TRACE_STOP, 0);
> if (preempt_trace() || irq_trace())
> stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
> }

Sebastian


2016-03-07 23:45:24

by Yang Shi

[permalink] [raw]
Subject: Re: [4.4-rt PATCH] trace: use rcuidle version for preemptoff_hist trace point

On 3/7/2016 10:00 AM, Sebastian Andrzej Siewior wrote:
> * Yang Shi | 2016-02-23 13:23:23 [-0800]:
>
>> I recall the rcuidle version is used by 4.1-rt, but not sure why it is dropped
>> in 4.4-rt. It looks such fix is still needed.
> I don't recall while I removed it. It was durring v4.1 -> v4.4 port. In
> v4.1 we had the idle version only in time_hardirqs_on() + …_off(). You
> introduced it also to start_critical_timings() + stop_…(). Is this
> required?

Yes, the test showed the same problem in start{stop}_critical_timings too.

> In the meantime I bring back the empty macro of
> trace_preemptirqsoff_hist_rcuidle() back in -RT sine it breaks compile
> latest v4.4.3-RT9

Yes, sorry to forget to bring this in too. The 4.1 patch was submitted
by me, but forgot to have it in 4.4.

Yang

>
>> kernel/trace/trace_irqsoff.c | 8 ++++----
>> 1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
>> index 36e584f..069942c 100644
>> --- a/kernel/trace/trace_irqsoff.c
>> +++ b/kernel/trace/trace_irqsoff.c
>> @@ -421,13 +421,13 @@ void start_critical_timings(void)
>> {
>> if (preempt_trace() || irq_trace())
>> start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
>> - trace_preemptirqsoff_hist(TRACE_START, 1);
>> + trace_preemptirqsoff_hist_rcuidle(TRACE_START, 1);
>> }
>> EXPORT_SYMBOL_GPL(start_critical_timings);
>>
>> void stop_critical_timings(void)
>> {
>> - trace_preemptirqsoff_hist(TRACE_STOP, 0);
>> + trace_preemptirqsoff_hist_rcuidle(TRACE_STOP, 0);
>> if (preempt_trace() || irq_trace())
>> stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
>> }
> Sebastian