Jan Kiszka wrote: > Jan Kiszka wrote: > >>... >>Meanwhile I found a solution for the described unterminated trace (put >>an explicite trace_end at the end of __ipipe_unstall_iret_root), >>included the irq number in the begin/end report, and stumbled over some >>other remaining unterminated trace on a different machine. So, no need >>to hurry with the merge (not the review! ;) ), I will publish a second >>revision first. >> > > > And here comes this revision finally. Should apply (almost) cleanly > against latest ipipe versions. Additionally to the changes of the first > revision this one addresses the following topics: > > o fix trace overrun handling > o report IRQ number to tracer on IRQ entry/exit > o fix virtually leaking IRQs-off in __ipipe_unstall_iret_root() > o fix another potential NMI race > o really trace the maximum IRQs-off time, not the maximum time of > consecutive IRQs-off times (that scenario will soon be addressed > instead in the latency benchmark tool => reset&freeze the maximum > latency from the user's point of view)
...and it turned out that the existing functions were no sufficient for
this. So here comes an add-on patch to update3:
o allow ipipe_trace_{frozen|max}_reset from every context
(well, at least give it a try and just fail on locked traces)
o mark border between valid and invalid trace points
o show invalid points border
Apply order:
ipipe_tracer.update3
ipipe_tracer.update3-1
The front-end to the first change, a modified latency+timerbench will
get committed to Xenomai soon. It already works nicely, automatically
creating a freeze of the maximum latency turn the benchmark perceives.
Jan
--- linux-2.6.14.3/kernel/ipipe/tracer.c.orig 2006-01-06 11:13:41.000000000
+0100
+++ linux-2.6.14.3/kernel/ipipe/tracer.c 2006-01-06 20:11:10.000000000
+0100
@@ -134,10 +134,14 @@ __ipipe_migrate_pre_trace(struct ipipe_t
int i;
new_tp->trace_pos = pre_trace+1;
+
for (i = new_tp->trace_pos; i > 0; i--)
memcpy(&new_tp->point[WRAP_POINT_NO(new_tp->trace_pos-i)],
&old_tp->point[WRAP_POINT_NO(old_pos-i)],
sizeof(struct ipipe_trace_point));
+
+ /* mark the end (i.e. the point before point[0]) invalid */
+ new_tp->point[IPIPE_TRACE_POINTS-1].eip = 0;
}
static notrace struct ipipe_trace_path *
@@ -436,21 +440,23 @@ void notrace ipipe_trace_special(unsigne
}
EXPORT_SYMBOL(ipipe_trace_special);
-void ipipe_trace_max_reset(void)
+int ipipe_trace_max_reset(void)
{
int cpu_id;
unsigned long flags;
struct ipipe_trace_path *path;
+ int ret = 0;
- /* only allowed from root domain (we sync with /proc routines) */
- if (ipipe_current_domain != ipipe_root_domain)
- return;
-
- down(&out_mutex);
flags = __ipipe_global_path_lock();
for_each_cpu(cpu_id) {
path = &trace_paths[cpu_id][max_path[cpu_id]];
+
+ if (path->dump_lock) {
+ ret = -EBUSY;
+ break;
+ }
+
path->begin = -1;
path->end = -1;
path->trace_pos = 0;
@@ -458,25 +464,28 @@ void ipipe_trace_max_reset(void)
}
__ipipe_global_path_unlock(flags);
- up(&out_mutex);
+
+ return ret;
}
EXPORT_SYMBOL(ipipe_trace_max_reset);
-void ipipe_trace_frozen_reset(void)
+int ipipe_trace_frozen_reset(void)
{
int cpu_id;
unsigned long flags;
struct ipipe_trace_path *path;
+ int ret = 0;
- /* only allowed from root domain (we sync with /proc routines) */
- if (ipipe_current_domain != ipipe_root_domain)
- return;
-
- down(&out_mutex);
flags = __ipipe_global_path_lock();
for_each_cpu(cpu_id) {
path = &trace_paths[cpu_id][frozen_path[cpu_id]];
+
+ if (path->dump_lock) {
+ ret = -EBUSY;
+ break;
+ }
+
path->begin = -1;
path->end = -1;
path->trace_pos = 0;
@@ -484,7 +493,8 @@ void ipipe_trace_frozen_reset(void)
}
__ipipe_global_path_unlock(flags);
- up(&out_mutex);
+
+ return ret;
}
EXPORT_SYMBOL(ipipe_trace_frozen_reset);
@@ -684,8 +694,10 @@ static int __ipipe_prtrace_show(struct s
unsigned long long abs_delta;
struct ipipe_trace_point *point = p;
- if (!point->eip)
+ if (!point->eip) {
+ seq_puts(m, "-<invalid>-\n");
return 0;
+ }
/* ipipe_tsc2us works on unsigned => handle sign separately */
delta = point->timestamp -
@@ -749,7 +761,10 @@ static ssize_t
__ipipe_max_reset(struct file *file, const char __user *pbuffer,
size_t count, loff_t *data)
{
+ down(&out_mutex);
ipipe_trace_max_reset();
+ up(&out_mutex);
+
return count;
}
@@ -841,7 +856,10 @@ static ssize_t
__ipipe_frozen_reset(struct file *file, const char __user *pbuffer,
size_t count, loff_t *data)
{
+ down(&out_mutex);
ipipe_trace_frozen_reset();
+ up(&out_mutex);
+
return count;
}
--- linux-2.6.14.3/include/linux/ipipe_trace.h.orig 2006-01-06
11:13:41.000000000 +0100
+++ linux-2.6.14.3/include/linux/ipipe_trace.h 2006-01-06 12:37:19.000000000
+0100
@@ -28,7 +28,7 @@ void ipipe_trace_end(unsigned long v);
void ipipe_trace_freeze(unsigned long v);
void ipipe_trace_special(unsigned char special_id, unsigned long v);
-void ipipe_trace_max_reset(void);
-void ipipe_trace_frozen_reset(void);
+int ipipe_trace_max_reset(void);
+int ipipe_trace_frozen_reset(void);
#endif /* !__LINUX_IPIPE_H */
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