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authorNamhyung Kim <namhyung@kernel.org>2016-03-03 12:55:02 -0600
committerSteven Rostedt <rostedt@goodmis.org>2016-04-19 18:56:03 -0400
commit4b94f5b7b4a5ffd885609bd033af2ecca0c9cc54 (patch)
tree529fee516eeaaf962f48423411aac8a34ee83ddd /kernel/trace
parent76929ab51f0ee398bcf72286c4b377051f07a31b (diff)
downloadlinux-sh-4b94f5b7b4a5ffd885609bd033af2ecca0c9cc54.tar.gz
tracing: Add hist trigger 'log2' modifier
Allow users to have numeric fields displayed as log2 values in case value range is very wide by appending '.log2' to field names. For example, # echo 'hist:key=bytes_req' > kmalloc/trigger # cat kmalloc/hist { bytes_req: 504 } hitcount: 1 { bytes_req: 11 } hitcount: 1 { bytes_req: 104 } hitcount: 1 { bytes_req: 48 } hitcount: 1 { bytes_req: 2048 } hitcount: 1 { bytes_req: 4096 } hitcount: 1 { bytes_req: 240 } hitcount: 1 { bytes_req: 392 } hitcount: 1 { bytes_req: 13 } hitcount: 1 { bytes_req: 28 } hitcount: 1 { bytes_req: 12 } hitcount: 1 { bytes_req: 64 } hitcount: 2 { bytes_req: 128 } hitcount: 2 { bytes_req: 32 } hitcount: 2 { bytes_req: 8 } hitcount: 11 { bytes_req: 10 } hitcount: 13 { bytes_req: 24 } hitcount: 25 { bytes_req: 160 } hitcount: 29 { bytes_req: 16 } hitcount: 33 { bytes_req: 80 } hitcount: 36 When using '.log2' modifier, the output looks like: # echo 'hist:key=bytes_req.log2' > kmalloc/trigger # cat kmalloc/hist { bytes_req: ~ 2^12 } hitcount: 1 { bytes_req: ~ 2^11 } hitcount: 1 { bytes_req: ~ 2^9 } hitcount: 2 { bytes_req: ~ 2^6 } hitcount: 3 { bytes_req: ~ 2^3 } hitcount: 13 { bytes_req: ~ 2^5 } hitcount: 19 { bytes_req: ~ 2^8 } hitcount: 49 { bytes_req: ~ 2^7 } hitcount: 57 { bytes_req: ~ 2^4 } hitcount: 74 Link: http://lkml.kernel.org/r/7ff396b246c6a881f46b979735fddf05a0d6c71a.1457029949.git.tom.zanussi@linux.intel.com Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/trace.c1
-rw-r--r--kernel/trace/trace_events_hist.c20
2 files changed, 21 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 4e342d354c12..988a35263fdd 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3872,6 +3872,7 @@ static const char readme_msg[] =
"\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 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_events_hist.c b/kernel/trace/trace_events_hist.c
index bdea5603cbde..23df38aab503 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -68,6 +68,13 @@ static u64 hist_field_pstring(struct hist_field *hist_field, void *event)
return (u64)(unsigned long)*addr;
}
+static u64 hist_field_log2(struct hist_field *hist_field, void *event)
+{
+ u64 val = *(u64 *)(event + hist_field->field->offset);
+
+ return (u64) ilog2(roundup_pow_of_two(val));
+}
+
#define DEFINE_HIST_FIELD_FN(type) \
static u64 hist_field_##type(struct hist_field *hist_field, void *event)\
{ \
@@ -111,6 +118,7 @@ enum hist_field_flags {
HIST_FIELD_FL_EXECNAME = 64,
HIST_FIELD_FL_SYSCALL = 128,
HIST_FIELD_FL_STACKTRACE = 256,
+ HIST_FIELD_FL_LOG2 = 512,
};
struct hist_trigger_attrs {
@@ -358,6 +366,11 @@ static struct hist_field *create_hist_field(struct ftrace_event_field *field,
goto out;
}
+ if (flags & HIST_FIELD_FL_LOG2) {
+ hist_field->fn = hist_field_log2;
+ goto out;
+ }
+
if (is_string_field(field)) {
flags |= HIST_FIELD_FL_STRING;
@@ -522,6 +535,8 @@ static int create_key_field(struct hist_trigger_data *hist_data,
flags |= HIST_FIELD_FL_EXECNAME;
else if (strcmp(field_str, "syscall") == 0)
flags |= HIST_FIELD_FL_SYSCALL;
+ else if (strcmp(field_str, "log2") == 0)
+ flags |= HIST_FIELD_FL_LOG2;
else {
ret = -EINVAL;
goto out;
@@ -980,6 +995,9 @@ hist_trigger_entry_print(struct seq_file *m,
key + key_field->offset,
HIST_STACKTRACE_DEPTH);
multiline = true;
+ } else if (key_field->flags & HIST_FIELD_FL_LOG2) {
+ seq_printf(m, "%s: ~ 2^%-2llu", key_field->field->name,
+ *(u64 *)(key + key_field->offset));
} else if (key_field->flags & HIST_FIELD_FL_STRING) {
seq_printf(m, "%s: %-50s", key_field->field->name,
(char *)(key + key_field->offset));
@@ -1112,6 +1130,8 @@ static const char *get_hist_field_flags(struct hist_field *hist_field)
flags_str = "execname";
else if (hist_field->flags & HIST_FIELD_FL_SYSCALL)
flags_str = "syscall";
+ else if (hist_field->flags & HIST_FIELD_FL_LOG2)
+ flags_str = "log2";
return flags_str;
}