From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <43BFC392.1000700@domain.hid> Date: Sat, 07 Jan 2006 14:35:14 +0100 From: Philippe Gerum MIME-Version: 1.0 Subject: Re: [Xenomai-core] Re: [PATCH] latency tracer update References: <43BC4FFB.8040709@domain.hid> <43BCF891.1080402@domain.hid> <43BCFFBB.1080303@domain.hid> <43BE4091.4020806@domain.hid> <43BEC786.8050504@domain.hid> In-Reply-To: <43BEC786.8050504@domain.hid> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: adeos-main@gna.org, xenomai-core Jan Kiszka wrote: > 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 > Merged in 1.1-03, with the appropriate tracer patch. Thanks. > 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, "--\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 */ -- Philippe.