From 4449bf927b61bdb4389393c6fea6837214d1ace7 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 6 May 2014 13:10:24 -0400 Subject: tracing: Add __bitmask() macro to trace events to cpumasks and other bitmasks Being able to show a cpumask of events can be useful as some events may affect only some CPUs. There is no standard way to record the cpumask and converting it to a string is rather expensive during the trace as traces happen in hotpaths. It would be better to record the raw event mask and be able to parse it at print time. The following macros were added for use with the TRACE_EVENT() macro: __bitmask() __assign_bitmask() __get_bitmask() To test this, I added this to the sched_migrate_task event, which looked like this: TRACE_EVENT(sched_migrate_task, TP_PROTO(struct task_struct *p, int dest_cpu, const struct cpumask *cpus), TP_ARGS(p, dest_cpu, cpus), TP_STRUCT__entry( __array( char, comm, TASK_COMM_LEN ) __field( pid_t, pid ) __field( int, prio ) __field( int, orig_cpu ) __field( int, dest_cpu ) __bitmask( cpumask, num_possible_cpus() ) ), TP_fast_assign( memcpy(__entry->comm, p->comm, TASK_COMM_LEN); __entry->pid = p->pid; __entry->prio = p->prio; __entry->orig_cpu = task_cpu(p); __entry->dest_cpu = dest_cpu; __assign_bitmask(cpumask, cpumask_bits(cpus), num_possible_cpus()); ), TP_printk("comm=%s pid=%d prio=%d orig_cpu=%d dest_cpu=%d cpumask=%s", __entry->comm, __entry->pid, __entry->prio, __entry->orig_cpu, __entry->dest_cpu, __get_bitmask(cpumask)) ); With the output of: ksmtuned-3613 [003] d..2 485.220508: sched_migrate_task: comm=ksmtuned pid=3615 prio=120 orig_cpu=3 dest_cpu=2 cpumask=00000000,0000000f migration/1-13 [001] d..5 485.221202: sched_migrate_task: comm=ksmtuned pid=3614 prio=120 orig_cpu=1 dest_cpu=0 cpumask=00000000,0000000f awk-3615 [002] d.H5 485.221747: sched_migrate_task: comm=rcu_preempt pid=7 prio=120 orig_cpu=0 dest_cpu=1 cpumask=00000000,000000ff migration/2-18 [002] d..5 485.222062: sched_migrate_task: comm=ksmtuned pid=3615 prio=120 orig_cpu=2 dest_cpu=3 cpumask=00000000,0000000f Link: http://lkml.kernel.org/r/1399377998-14870-6-git-send-email-javi.merino@arm.com Link: http://lkml.kernel.org/r/20140506132238.22e136d1@gandalf.local.home Suggested-by: Javi Merino Tested-by: Javi Merino Signed-off-by: Steven Rostedt --- include/trace/ftrace.h | 57 +++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 56 insertions(+), 1 deletion(-) (limited to 'include/trace') diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 0a1a4f7caf09..9b7a989dcbcc 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -53,6 +53,9 @@ #undef __string #define __string(item, src) __dynamic_array(char, item, -1) +#undef __bitmask +#define __bitmask(item, nr_bits) __dynamic_array(char, item, -1) + #undef TP_STRUCT__entry #define TP_STRUCT__entry(args...) args @@ -128,6 +131,9 @@ #undef __string #define __string(item, src) __dynamic_array(char, item, -1) +#undef __bitmask +#define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1) + #undef DECLARE_EVENT_CLASS #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \ struct ftrace_data_offsets_##call { \ @@ -200,6 +206,15 @@ #undef __get_str #define __get_str(field) (char *)__get_dynamic_array(field) +#undef __get_bitmask +#define __get_bitmask(field) \ + ({ \ + void *__bitmask = __get_dynamic_array(field); \ + unsigned int __bitmask_size; \ + __bitmask_size = (__entry->__data_loc_##field >> 16) & 0xffff; \ + ftrace_print_bitmask_seq(p, __bitmask, __bitmask_size); \ + }) + #undef __print_flags #define __print_flags(flag, delim, flag_array...) \ ({ \ @@ -322,6 +337,9 @@ static struct trace_event_functions ftrace_event_type_funcs_##call = { \ #undef __string #define __string(item, src) __dynamic_array(char, item, -1) +#undef __bitmask +#define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1) + #undef DECLARE_EVENT_CLASS #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, func, print) \ static int notrace __init \ @@ -372,6 +390,29 @@ ftrace_define_fields_##call(struct ftrace_event_call *event_call) \ #define __string(item, src) __dynamic_array(char, item, \ strlen((src) ? (const char *)(src) : "(null)") + 1) +/* + * __bitmask_size_in_bytes_raw is the number of bytes needed to hold + * num_possible_cpus(). + */ +#define __bitmask_size_in_bytes_raw(nr_bits) \ + (((nr_bits) + 7) / 8) + +#define __bitmask_size_in_longs(nr_bits) \ + ((__bitmask_size_in_bytes_raw(nr_bits) + \ + ((BITS_PER_LONG / 8) - 1)) / (BITS_PER_LONG / 8)) + +/* + * __bitmask_size_in_bytes is the number of bytes needed to hold + * num_possible_cpus() padded out to the nearest long. This is what + * is saved in the buffer, just to be consistent. + */ +#define __bitmask_size_in_bytes(nr_bits) \ + (__bitmask_size_in_longs(nr_bits) * (BITS_PER_LONG / 8)) + +#undef __bitmask +#define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, \ + __bitmask_size_in_longs(nr_bits)) + #undef DECLARE_EVENT_CLASS #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \ static inline notrace int ftrace_get_offsets_##call( \ @@ -513,12 +554,22 @@ static inline notrace int ftrace_get_offsets_##call( \ __entry->__data_loc_##item = __data_offsets.item; #undef __string -#define __string(item, src) __dynamic_array(char, item, -1) \ +#define __string(item, src) __dynamic_array(char, item, -1) #undef __assign_str #define __assign_str(dst, src) \ strcpy(__get_str(dst), (src) ? (const char *)(src) : "(null)"); +#undef __bitmask +#define __bitmask(item, nr_bits) __dynamic_array(unsigned long, item, -1) + +#undef __get_bitmask +#define __get_bitmask(field) (char *)__get_dynamic_array(field) + +#undef __assign_bitmask +#define __assign_bitmask(dst, src, nr_bits) \ + memcpy(__get_bitmask(dst), (src), __bitmask_size_in_bytes(nr_bits)) + #undef TP_fast_assign #define TP_fast_assign(args...) args @@ -586,6 +637,7 @@ static inline void ftrace_test_probe_##call(void) \ #undef __print_hex #undef __get_dynamic_array #undef __get_str +#undef __get_bitmask #undef TP_printk #define TP_printk(fmt, args...) "\"" fmt "\", " __stringify(args) @@ -651,6 +703,9 @@ __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call #undef __get_str #define __get_str(field) (char *)__get_dynamic_array(field) +#undef __get_bitmask +#define __get_bitmask(field) (char *)__get_dynamic_array(field) + #undef __perf_addr #define __perf_addr(a) (__addr = (a)) -- cgit v1.2.3 From beba4bb096201ceec0e8cfb7ce3172a53015bdaf Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 4 Jun 2014 14:29:33 -0400 Subject: tracing: Add __get_dynamic_array_len() macro for trace events If a trace event uses a dynamic array for something other than a string then there's currently no way the TP_printk() can figure out what size it is. A __get_dynamic_array_len() is required to know the length. This also simplifies the __get_bitmask() macro which required it as well, but instead just hardcoded it. Signed-off-by: Steven Rostedt --- include/trace/ftrace.h | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'include/trace') diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 9b7a989dcbcc..0fd06fef9fac 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -203,6 +203,10 @@ #define __get_dynamic_array(field) \ ((void *)__entry + (__entry->__data_loc_##field & 0xffff)) +#undef __get_dynamic_array_len +#define __get_dynamic_array_len(field) \ + ((__entry->__data_loc_##field >> 16) & 0xffff) + #undef __get_str #define __get_str(field) (char *)__get_dynamic_array(field) @@ -211,7 +215,7 @@ ({ \ void *__bitmask = __get_dynamic_array(field); \ unsigned int __bitmask_size; \ - __bitmask_size = (__entry->__data_loc_##field >> 16) & 0xffff; \ + __bitmask_size = __get_dynamic_array_len(field); \ ftrace_print_bitmask_seq(p, __bitmask, __bitmask_size); \ }) @@ -636,6 +640,7 @@ static inline void ftrace_test_probe_##call(void) \ #undef __print_symbolic #undef __print_hex #undef __get_dynamic_array +#undef __get_dynamic_array_len #undef __get_str #undef __get_bitmask @@ -700,6 +705,10 @@ __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call #define __get_dynamic_array(field) \ ((void *)__entry + (__entry->__data_loc_##field & 0xffff)) +#undef __get_dynamic_array_len +#define __get_dynamic_array_len(field) \ + ((__entry->__data_loc_##field >> 16) & 0xffff) + #undef __get_str #define __get_str(field) (char *)__get_dynamic_array(field) -- cgit v1.2.3