From: Tom Zanussi Appending .usecs onto a common_timestamp field will cause the timestamp value to be in microseconds instead of the default nanoseconds. A typical latency histogram using usecs would look like this: # echo 'hist:keys=pid,prio:ts0=common_timestamp.usecs ... # echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0 ... This also adds an external trace_clock_in_ns() to trace.c for the timestamp conversion. Link: http://lkml.kernel.org/r/4e813705a170b3e13e97dc3135047362fb1a39f3.1516069914.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (VMware) --- Documentation/trace/histogram.txt | 1 + kernel/trace/trace.c | 13 +++++++++++-- kernel/trace/trace.h | 2 ++ kernel/trace/trace_events_hist.c | 28 ++++++++++++++++++++++------ 4 files changed, 36 insertions(+), 8 deletions(-) diff --git a/Documentation/trace/histogram.txt b/Documentation/trace/histogram.txt index a4143f04a097..25c94730d3fe 100644 --- a/Documentation/trace/histogram.txt +++ b/Documentation/trace/histogram.txt @@ -74,6 +74,7 @@ .syscall display a syscall id as a system call name .execname display a common_pid as a program name .log2 display log2 value rather than raw number + .usecs display a common_timestamp in microseconds Note that in general the semantics of a given field aren't interpreted when applying a modifier to it, but there are some diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 988d94a05e81..82cc8891fda6 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1168,6 +1168,14 @@ static struct { ARCH_TRACE_CLOCKS }; +bool trace_clock_in_ns(struct trace_array *tr) +{ + if (trace_clocks[tr->clock_id].in_ns) + return true; + + return false; +} + /* * trace_parser_get_init - gets the buffer for trace parser */ @@ -4694,8 +4702,9 @@ static const char readme_msg[] = "\t .sym display an address as a symbol\n" "\t .sym-offset display an address as a symbol and offset\n" "\t .execname display a common_pid as a program name\n" - "\t .syscall display a syscall id as a syscall name\n\n" - "\t .log2 display log2 value rather than raw number\n\n" + "\t .syscall display a syscall id as a syscall name\n" + "\t .log2 display log2 value rather than raw number\n" + "\t .usecs display a common_timestamp in microseconds\n\n" "\t The 'pause' parameter can be used to pause an existing hist\n" "\t trigger or to start a hist trigger but not log any events\n" "\t until told to do so. 'continue' can be used to start or\n" diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 99060f7eebbd..89771b4f16df 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -289,6 +289,8 @@ extern void trace_array_put(struct trace_array *tr); extern int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs); +extern bool trace_clock_in_ns(struct trace_array *tr); + /* * The global tracer (top) should be the first trace array added, * but we check the flag anyway. diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 77ebe6b410ba..7f5f0b8f6558 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -90,12 +90,6 @@ static u64 hist_field_log2(struct hist_field *hist_field, void *event, return (u64) ilog2(roundup_pow_of_two(val)); } -static u64 hist_field_timestamp(struct hist_field *hist_field, void *event, - struct ring_buffer_event *rbe) -{ - return ring_buffer_event_time_stamp(rbe); -} - #define DEFINE_HIST_FIELD_FN(type) \ static u64 hist_field_##type(struct hist_field *hist_field, \ void *event, \ @@ -143,6 +137,7 @@ enum hist_field_flags { HIST_FIELD_FL_STACKTRACE = 1 << 8, HIST_FIELD_FL_LOG2 = 1 << 9, HIST_FIELD_FL_TIMESTAMP = 1 << 10, + HIST_FIELD_FL_TIMESTAMP_USECS = 1 << 11, }; struct hist_trigger_attrs { @@ -153,6 +148,7 @@ struct hist_trigger_attrs { bool pause; bool cont; bool clear; + bool ts_in_usecs; unsigned int map_bits; }; @@ -170,6 +166,20 @@ struct hist_trigger_data { bool enable_timestamps; }; +static u64 hist_field_timestamp(struct hist_field *hist_field, void *event, + struct ring_buffer_event *rbe) +{ + struct hist_trigger_data *hist_data = hist_field->hist_data; + struct trace_array *tr = hist_data->event_file->tr; + + u64 ts = ring_buffer_event_time_stamp(rbe); + + if (hist_data->attrs->ts_in_usecs && trace_clock_in_ns(tr)) + ts = ns2usecs(ts); + + return ts; +} + static const char *hist_field_name(struct hist_field *field, unsigned int level) { @@ -634,6 +644,8 @@ static int create_key_field(struct hist_trigger_data *hist_data, flags |= HIST_FIELD_FL_SYSCALL; else if (strcmp(field_str, "log2") == 0) flags |= HIST_FIELD_FL_LOG2; + else if (strcmp(field_str, "usecs") == 0) + flags |= HIST_FIELD_FL_TIMESTAMP_USECS; else { ret = -EINVAL; goto out; @@ -643,6 +655,8 @@ static int create_key_field(struct hist_trigger_data *hist_data, if (strcmp(field_name, "common_timestamp") == 0) { flags |= HIST_FIELD_FL_TIMESTAMP; hist_data->enable_timestamps = true; + if (flags & HIST_FIELD_FL_TIMESTAMP_USECS) + hist_data->attrs->ts_in_usecs = true; key_size = sizeof(u64); } else { field = trace_find_event_field(file->event_call, field_name); @@ -1241,6 +1255,8 @@ static const char *get_hist_field_flags(struct hist_field *hist_field) flags_str = "syscall"; else if (hist_field->flags & HIST_FIELD_FL_LOG2) flags_str = "log2"; + else if (hist_field->flags & HIST_FIELD_FL_TIMESTAMP_USECS) + flags_str = "usecs"; return flags_str; } -- 2.15.1