On Tue, Oct 12, 2010 at 6:56 AM, wu zhangjin <[email protected]> wrote: > On Mon, Oct 11, 2010 at 10:00 PM, Jack Daniel <[email protected]> > wrote: >> On Thu, Oct 7, 2010 at 8:30 PM, wu zhangjin <[email protected]> wrote: >>> Hi, Jack >>> >>> On 10/7/10, Jack Daniel <[email protected]> wrote: >>>> Hi Wu, >>>> >>>> I was going through your latency tracing implementation for loongson. >>>> Could you please assist me in understanding the following. >>>> >>>> 1) How is the latency tracing implemented here different from ftrace >>>> tracer function "irqsoff" ? "irqsoff" calculates the time when >>>> interrupts are disabled. >>> >>> What do you mean "the latency tracing implemented here"? In reality, >>> the latency tracers I have used are the ones you said above: irqsoff >>> tracer, preemptoff tracer and preemptirqsoff tracer, wakeup tracer ... >> >> My apologies for not articulating my question properly. What I meant >> was the latency tracing support available at >> Device Drivers ---> [*] PREEMPT_RT Specific Device Drivers ---> >> <*> Interrupt Latency Driver >> I see that you are the only one to support this in your tree for >> loongson. How different is this from "irqsoff" supported by Ftrace? >> > > The "Interrupt latency driver" differs from the irqsoff tracer, it > tries to measure the time between the interrupt emitted and the > interrupt is really handled, it reflects the response time of an > interrupt. > > Perhaps you can write such one driver for octeon via the RTC driver > (if your board has such a driver) for we can use RTC to generate > interrupt, For Loongson, I have used the MFGPT timer.
Thank you for taking the time to explain this concept. I will try and implement this tracing method for Octeon by using RTC. First I will need to study your code. Thank you once again. Regards, Jack -- You received this message because you are subscribed to the Google Groups "loongson-dev" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/loongson-dev?hl=en.
