From dd0e545f061f90099a3dcc13aa77e29c6295cf23 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Fri, 1 Aug 2008 12:26:41 -0400 Subject: ftrace: printk formatting infrastructure This patch adds a feature that can help kernel developers debug their code using ftrace. int ftrace_printk(const char *fmt, ...); This records into the ftrace buffer using printf formatting. The entry size in the buffers are still a fixed length. A new type has been added that allows for more entries to be used for a single recording. The start of the print is still the same as the other entries. It returns the number of characters written to the ftrace buffer. For example: Having a module with the following code: static int __init ftrace_print_test(void) { ftrace_printk("jiffies are %ld\n", jiffies); return 0; } Gives me: insmod-5441 3...1 7569us : ftrace_print_test: jiffies are 4296626666 for the latency_trace file and: insmod-5441 [03] 1959.370498: ftrace_print_test jiffies are 4296626666 for the trace file. Note: Only the infrastructure should go into the kernel. It is to help facilitate debugging for other kernel developers. Calls to ftrace_printk is not intended to be left in the kernel, and should be frowned upon just like scattering printks around in the code. But having this easily at your fingertips helps the debugging go faster and bugs be solved quicker. Maybe later on, we can hook this with markers and have their printf format be sucked into ftrace output. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace_selftest.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) (limited to 'kernel/trace/trace_selftest.c') diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 0911b7e073bf..630715bbd572 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -9,7 +9,9 @@ static inline int trace_valid_entry(struct trace_entry *entry) case TRACE_FN: case TRACE_CTX: case TRACE_WAKE: + case TRACE_CONT: case TRACE_STACK: + case TRACE_PRINT: case TRACE_SPECIAL: return 1; } @@ -120,11 +122,11 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace, struct trace_array *tr, int (*func)(void)) { - unsigned long count; - int ret; int save_ftrace_enabled = ftrace_enabled; int save_tracer_enabled = tracer_enabled; + unsigned long count; char *func_name; + int ret; /* The ftrace test PASSED */ printk(KERN_CONT "PASSED\n"); @@ -157,6 +159,7 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace, /* enable tracing */ tr->ctrl = 1; trace->init(tr); + /* Sleep for a 1/10 of a second */ msleep(100); @@ -212,10 +215,10 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace, int trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr) { - unsigned long count; - int ret; int save_ftrace_enabled = ftrace_enabled; int save_tracer_enabled = tracer_enabled; + unsigned long count; + int ret; /* make sure msleep has been recorded */ msleep(1); -- cgit v1.2.2 From fb1b6d8b5154c692172a424e45fbd0573295cb93 Mon Sep 17 00:00:00 2001 From: Steven Noonan Date: Fri, 19 Sep 2008 03:06:43 -0700 Subject: ftrace: add nop tracer A no-op tracer which can serve two purposes: 1. A template for development of a new tracer. 2. A convenient way to see ftrace_printk() calls without an irrelevant trace making the output messy. [ mingo@elte.hu: resolved conflicts ] Signed-off-by: Steven Noonan Signed-off-by: Ingo Molnar --- kernel/trace/trace_selftest.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'kernel/trace/trace_selftest.c') diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 630715bbd572..82db9103b9bc 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -418,6 +418,15 @@ trace_selftest_startup_preemptirqsoff(struct tracer *trace, struct trace_array * } #endif /* CONFIG_IRQSOFF_TRACER && CONFIG_PREEMPT_TRACER */ +#ifdef CONFIG_NOP_TRACER +int +trace_selftest_startup_nop(struct tracer *trace, struct trace_array *tr) +{ + /* What could possibly go wrong? */ + return 0; +} +#endif + #ifdef CONFIG_SCHED_TRACER static int trace_wakeup_test_thread(void *data) { -- cgit v1.2.2 From 5aa60c6073456812251caf9177cb921b2de68f77 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 29 Sep 2008 23:02:37 -0400 Subject: ftrace: give time for wakeup test to run It is possible that the testing thread in the ftrace wakeup test does not run before we stop the trace. This will cause the trace to fail since nothing will be in the buffers. This patch adds a small wait in the wakeup test to allow for the woken task to run and be traced. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace_selftest.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel/trace/trace_selftest.c') diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 82db9103b9bc..5ebd4b135498 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -498,6 +498,9 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr) wake_up_process(p); + /* give a little time to let the thread wake up */ + msleep(100); + /* stop the tracing. */ tr->ctrl = 0; trace->ctrl_update(tr); -- cgit v1.2.2 From 3928a8a2d98081d1bc3c0a84a2d70e29b90ecf1c Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 29 Sep 2008 23:02:41 -0400 Subject: ftrace: make work with new ring buffer This patch ports ftrace over to the new ring buffer. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace_selftest.c | 60 ++++++++----------------------------------- 1 file changed, 10 insertions(+), 50 deletions(-) (limited to 'kernel/trace/trace_selftest.c') diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 5ebd4b135498..09cf230d7eca 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -18,58 +18,20 @@ static inline int trace_valid_entry(struct trace_entry *entry) return 0; } -static int -trace_test_buffer_cpu(struct trace_array *tr, struct trace_array_cpu *data) +static int trace_test_buffer_cpu(struct trace_array *tr, int cpu) { - struct trace_entry *entries; - struct page *page; - int idx = 0; - int i; + struct ring_buffer_event *event; + struct trace_entry *entry; - BUG_ON(list_empty(&data->trace_pages)); - page = list_entry(data->trace_pages.next, struct page, lru); - entries = page_address(page); + while ((event = ring_buffer_consume(tr->buffer, cpu, NULL))) { + entry = ring_buffer_event_data(event); - check_pages(data); - if (head_page(data) != entries) - goto failed; - - /* - * The starting trace buffer always has valid elements, - * if any element exists. - */ - entries = head_page(data); - - for (i = 0; i < tr->entries; i++) { - - if (i < data->trace_idx && !trace_valid_entry(&entries[idx])) { + if (!trace_valid_entry(entry)) { printk(KERN_CONT ".. invalid entry %d ", - entries[idx].type); + entry->type); goto failed; } - - idx++; - if (idx >= ENTRIES_PER_PAGE) { - page = virt_to_page(entries); - if (page->lru.next == &data->trace_pages) { - if (i != tr->entries - 1) { - printk(KERN_CONT ".. entries buffer mismatch"); - goto failed; - } - } else { - page = list_entry(page->lru.next, struct page, lru); - entries = page_address(page); - } - idx = 0; - } - } - - page = virt_to_page(entries); - if (page->lru.next != &data->trace_pages) { - printk(KERN_CONT ".. too many entries"); - goto failed; } - return 0; failed: @@ -91,13 +53,11 @@ static int trace_test_buffer(struct trace_array *tr, unsigned long *count) /* Don't allow flipping of max traces now */ raw_local_irq_save(flags); __raw_spin_lock(&ftrace_max_lock); - for_each_possible_cpu(cpu) { - if (!head_page(tr->data[cpu])) - continue; - cnt += tr->data[cpu]->trace_idx; + cnt = ring_buffer_entries(tr->buffer); - ret = trace_test_buffer_cpu(tr, tr->data[cpu]); + for_each_possible_cpu(cpu) { + ret = trace_test_buffer_cpu(tr, cpu); if (ret) break; } -- cgit v1.2.2 From 606576ce816603d9fe1fb453a88bc6eea16ca709 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Mon, 6 Oct 2008 19:06:12 -0400 Subject: ftrace: rename FTRACE to FUNCTION_TRACER Due to confusion between the ftrace infrastructure and the gcc profiling tracer "ftrace", this patch renames the config options from FTRACE to FUNCTION_TRACER. The other two names that are offspring from FTRACE DYNAMIC_FTRACE and FTRACE_MCOUNT_RECORD will stay the same. This patch was generated mostly by script, and partially by hand. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace_selftest.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/trace/trace_selftest.c') diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 09cf230d7eca..95815d26a041 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -70,7 +70,7 @@ static int trace_test_buffer(struct trace_array *tr, unsigned long *count) return ret; } -#ifdef CONFIG_FTRACE +#ifdef CONFIG_FUNCTION_TRACER #ifdef CONFIG_DYNAMIC_FTRACE @@ -226,7 +226,7 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr) return ret; } -#endif /* CONFIG_FTRACE */ +#endif /* CONFIG_FUNCTION_TRACER */ #ifdef CONFIG_IRQSOFF_TRACER int -- cgit v1.2.2 From cb7be3b2fc2cf089ee52b16f0fd9ebb29e9944e1 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 23 Oct 2008 09:33:05 -0400 Subject: ftrace: remove daemon The ftrace daemon is complex and error prone. This patch strips it out of the code. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar --- kernel/trace/trace_selftest.c | 14 -------------- 1 file changed, 14 deletions(-) (limited to 'kernel/trace/trace_selftest.c') diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 95815d26a041..90bc752a7580 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -99,13 +99,6 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace, /* passed in by parameter to fool gcc from optimizing */ func(); - /* update the records */ - ret = ftrace_force_update(); - if (ret) { - printk(KERN_CONT ".. ftraced failed .. "); - return ret; - } - /* * Some archs *cough*PowerPC*cough* add charachters to the * start of the function names. We simply put a '*' to @@ -183,13 +176,6 @@ trace_selftest_startup_function(struct tracer *trace, struct trace_array *tr) /* make sure msleep has been recorded */ msleep(1); - /* force the recorded functions to be traced */ - ret = ftrace_force_update(); - if (ret) { - printk(KERN_CONT ".. ftraced failed .. "); - return ret; - } - /* start the tracing */ ftrace_enabled = 1; tracer_enabled = 1; -- cgit v1.2.2