Dear Alan,
Ok, I will apply patch and test again. Since time difference issue, I
can not do test now. It will be done when I back to office.
In advance, the question:
get_cpu_cycles() just get current count, right?
it is not necessary to do calculation of (exit point - enter point), right?
or it also do the calculation then retrun the count?
Thanks!
Soho
2011/6/3 Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>:
> On Fri, 3 Jun 2011, Soho Soho123 wrote:
>
>> Dear Alan,
>>
>>
>> the attached is log file about cpu cycle measurement. there are 2
>> files included in tar file.
>> 1. 0603_log_3.txt is cpu cycle data that I dump when urb submit error occur
>> 2. scan_periodic.c is the code that shows where I put enter point and
>> exit point.
>> I set a flag to disable update CPU Cycle count when urb submit error.
>> the data is saved into array .
>> "big for loop" ,"restart label","itd_complete" has a 4096 elements
>> array to save data, respectively.
>> the data type is :
>> struct for_loop_stat{
>> unsigned long long cpu_cycle_count;
>> unsigned int now_uframe;
>> unsigned int clock;
>> unsigned int modified;
>> };
>> the element "modified" is used for restart_lable only.
>> if modified is "1", it means the data from "restart" to "goto restart"
>> in 0603_log_3.txt, the first line shows the index of each array when
>> the error is occur.
>
> Unfortunately the data in your file doesn't make much sense to me.
> Since you stop collecting data when the submit error occurs, each of
> the three arrays should end with the same value for now_uframe (or
> almost the same value). But they don't. The "big for loop" array ends
> with now_uframe = 2319, the "restart label" array ends with now_uframe
> = 201, and the "itd_complete" array ends with now_uframe = 1240.
>
> Anyway, this wasn't what I wanted you to do. I'd like to see the data
> all in a single array. The patch below shows how to arrange it.
>
> You have a routine to get the current CPU cycle counter, right? I
> don't know what its name is, so in the patch it's called
> get_cpu_cycles(). You'll have to fix that up.
>
> Alan Stern
>
>
>
> Index: usb-3.0/drivers/usb/host/ehci-sched.c
> ===================================================================
> --- usb-3.0.orig/drivers/usb/host/ehci-sched.c
> +++ usb-3.0/drivers/usb/host/ehci-sched.c
> @@ -19,6 +19,56 @@
>
> /* this file is part of ehci-hcd.c */
>
> +struct counter_stat {
> + unsigned long long cpu_cycle_count;
> + unsigned now_uframe;
> + unsigned clock;
> + int where;
> +};
> +
> +#define MAX_COUNTER_STAT 4000
> +
> +static struct counter_stat stats[MAX_COUNTER_STAT];
> +static int next_stat;
> +static int stats_flag = 1;
> +
> +static void update_counter_stats(unsigned now_uframe, unsigned clock,
> + int where)
> +{
> + static unsigned long long cpu_cycles;
> + unsigned long long c2;
> + extern unsigned long long get_cpu_cycles(void);
> +
> + if (!stats_flag)
> + return;
> +
> + c2 = get_cpu_cycles();
> + stats[next_stat].cpu_cycle_count = c2 - cpu_cycles;
> + cpu_cycles = c2;
> + stats[next_stat].now_uframe = now_uframe;
> + stats[next_stat].clock = clock;
> + stats[next_stat].where = where;
> +
> + if (++next_stat == MAX_COUNTER_STAT)
> + next_stat = 0;
> +}
> +
> +static void dump_stats(void)
> +{
> + int i = next_stat;
> +
> + do {
> + printk(KERN_DEBUG "stat[%d]: now_uframe %u clock %u"
> + " where %d cycles %llu\n",
> + i, stats[i].now_uframe,
> + stats[i].clock,
> + stats[i].where,
> + stats[i].cpu_cycle_count);
> + if (++i == MAX_COUNTER_STAT)
> + i = 0;
> + } while (i != next_stat);
> +}
> +
> /*-------------------------------------------------------------------------*/
>
> /*
> @@ -1496,6 +1546,10 @@ iso_stream_schedule (
> urb, start - now, span - period,
> mod - 2 * SCHEDULE_SLOP);
> status = -EFBIG;
> + if (stats_flag) {
> + stats_flag = 0;
> + dump_stats();
> + }
> goto fail;
> }
>
> @@ -2293,6 +2347,8 @@ scan_periodic (struct ehci_hcd *ehci)
> clock_frame = clock >> 3;
> ++ehci->periodic_stamp;
>
> + update_counter_stats(now_uframe, clock, 1);
> +
> for (;;) {
> union ehci_shadow q, *q_p;
> __hc32 type, *hw_p;
> @@ -2301,6 +2357,7 @@ scan_periodic (struct ehci_hcd *ehci)
> frame = now_uframe >> 3;
>
> restart:
> + update_counter_stats(now_uframe, clock, 2);
> /* scan each element in frame's queue for completions */
> q_p = &ehci->pshadow [frame];
> hw_p = &ehci->periodic [frame];
> @@ -2378,6 +2435,7 @@ restart:
> type = Q_NEXT_TYPE(ehci, q.itd->hw_next);
> wmb();
> modified = itd_complete (ehci, q.itd);
> + update_counter_stats(now_uframe, clock, 3);
> q = *q_p;
> break;
> case Q_TYPE_SITD:
>
>
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