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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