From 5d4a9dba2d7fbab69f00dedd430d1788834a055a Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 27 Aug 2009 16:52:21 -0400 Subject: tracing: only show tracing_max_latency when latency tracer configured The tracing_max_latency file should only be present when one of the latency tracers ({preempt|irqs}off, wakeup*) are enabled. This patch also removes tracing_thresh when latency tracers are not enabled, as well as compiles out code that is only used for latency tracers. Reported-by: Arnaldo Carvalho de Melo Signed-off-by: Steven Rostedt --- kernel/trace/trace.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'kernel/trace/trace.h') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 654fd657bd03..e2c06b21dd82 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -473,12 +473,14 @@ void unregister_tracer(struct tracer *type); extern unsigned long nsecs_to_usecs(unsigned long nsecs); +#ifdef CONFIG_TRACER_MAX_TRACE extern unsigned long tracing_max_latency; extern unsigned long tracing_thresh; void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu); void update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu); +#endif /* CONFIG_TRACER_MAX_TRACE */ #ifdef CONFIG_STACKTRACE void ftrace_trace_stack(struct trace_array *tr, unsigned long flags, -- cgit v1.2.3 From 8248ac052dfd1eb41819fbc0ca5c7a1667e7e70c Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2009 12:27:41 -0400 Subject: tracing: print out start and stop in latency traces During development of the tracer, we would copy information from the live tracer to the max tracer with one memcpy. Since then we added a generic ring buffer and we handle the copies differently now. Unfortunately, we never copied the critical section information, and we lost the output: # => started at: kmem_cache_alloc # => ended at: kmem_cache_alloc This patch adds back the critical start and end copying as well as removes the unused "trace_idx" and "overrun" fields of the trace_array_cpu structure. Signed-off-by: Steven Rostedt --- kernel/trace/trace.h | 3 --- 1 file changed, 3 deletions(-) (limited to 'kernel/trace/trace.h') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index e2c06b21dd82..f2af713a8bcc 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -234,9 +234,6 @@ struct trace_array_cpu { atomic_t disabled; void *buffer_page; /* ring buffer spare */ - /* these fields get copied into max-trace: */ - unsigned long trace_idx; - unsigned long overrun; unsigned long saved_latency; unsigned long critical_start; unsigned long critical_end; -- cgit v1.2.3 From 2f26ebd549b9ab55ac756b836ec759c11fe93f81 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 1 Sep 2009 11:06:29 -0400 Subject: tracing: use timestamp to determine start of latency traces Currently the latency tracers reset the ring buffer. Unfortunately if a commit is in process (due to a trace event), this can corrupt the ring buffer. When this happens, the ring buffer will detect the corruption and then permanently disable the ring buffer. The bug does not crash the system, but it does prevent further tracing after the bug is hit. Instead of reseting the trace buffers, the timestamp of the start of the trace is used instead. The buffers will still contain the previous data, but the output will not count any data that is before the timestamp of the trace. Note, this only affects the static trace output (trace) and not the runtime trace output (trace_pipe). The runtime trace output does not make sense for the latency tracers anyway. Reported-by: Arnaldo Carvalho de Melo Signed-off-by: Steven Rostedt --- kernel/trace/trace.h | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/trace/trace.h') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index f2af713a8bcc..ca070de36227 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -241,6 +241,7 @@ struct trace_array_cpu { unsigned long nice; unsigned long policy; unsigned long rt_priority; + unsigned long skipped_entries; cycle_t preempt_timestamp; pid_t pid; uid_t uid; -- cgit v1.2.3 From e77405ad80f53966524b5c31244e13fbbbecbd84 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2009 14:17:06 -0400 Subject: tracing: pass around ring buffer instead of tracer The latency tracers (irqsoff and wakeup) can swap trace buffers on the fly. If an event is happening and has reserved data on one of the buffers, and the latency tracer swaps the global buffer with the max buffer, the result is that the event may commit the data to the wrong buffer. This patch changes the API to the trace recording to be recieve the buffer that was used to reserve a commit. Then this buffer can be passed in to the commit. Signed-off-by: Steven Rostedt --- kernel/trace/trace.h | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) (limited to 'kernel/trace/trace.h') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index ca070de36227..4d30414fe19a 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -415,12 +415,13 @@ void init_tracer_sysprof_debugfs(struct dentry *d_tracer); struct ring_buffer_event; -struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr, - int type, - unsigned long len, - unsigned long flags, - int pc); -void trace_buffer_unlock_commit(struct trace_array *tr, +struct ring_buffer_event * +trace_buffer_lock_reserve(struct ring_buffer *buffer, + int type, + unsigned long len, + unsigned long flags, + int pc); +void trace_buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event, unsigned long flags, int pc); @@ -481,10 +482,10 @@ void update_max_tr_single(struct trace_array *tr, #endif /* CONFIG_TRACER_MAX_TRACE */ #ifdef CONFIG_STACKTRACE -void ftrace_trace_stack(struct trace_array *tr, unsigned long flags, +void ftrace_trace_stack(struct ring_buffer *buffer, unsigned long flags, int skip, int pc); -void ftrace_trace_userstack(struct trace_array *tr, unsigned long flags, +void ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc); void __trace_stack(struct trace_array *tr, unsigned long flags, int skip, -- cgit v1.2.3 From 659372d3e42a3e17a2e042d38a8bcdb94bfbe797 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 3 Sep 2009 19:11:07 -0400 Subject: tracing: add trace_array_printk for internal tracers to use This patch adds a trace_array_printk to allow a tracer to use the trace_printk on its own trace array. Signed-off-by: Steven Rostedt --- kernel/trace/trace.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'kernel/trace/trace.h') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 4d30414fe19a..fa1dccb579d5 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -566,6 +566,11 @@ extern int trace_vbprintk(unsigned long ip, const char *fmt, va_list args); extern int trace_vprintk(unsigned long ip, const char *fmt, va_list args); +extern int +trace_array_vprintk(struct trace_array *tr, + unsigned long ip, const char *fmt, va_list args); +int trace_array_printk(struct trace_array *tr, + unsigned long ip, const char *fmt, ...); extern unsigned long trace_flags; -- cgit v1.2.3