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Date: Wed, 24 Feb 2016 12:31:57 -0600 From: Tom Zanussi <tom.zanussi@...ux.intel.com> To: rostedt@...dmis.org Cc: masami.hiramatsu.pt@...achi.com, namhyung@...nel.org, josh@...htriplett.org, andi@...stfloor.org, mathieu.desnoyers@...icios.com, peterz@...radead.org, linux-kernel@...r.kernel.org, Tom Zanussi <tom.zanussi@...ux.intel.com> Subject: [PATCH v14 22/22] tracing: Add hist trigger 'log2' modifier From: Namhyung Kim <namhyung@...nel.org> 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 Cc: Tom Zanussi <tom.zanussi@...ux.intel.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com> Signed-off-by: Namhyung Kim <namhyung@...nel.org> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com> Signed-off-by: Tom Zanussi <tom.zanussi@...ux.intel.com> --- kernel/trace/trace.c | 1 + kernel/trace/trace_events_hist.c | 20 ++++++++++++++++++++ 2 files changed, 21 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index ce8b885..7abfd25 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3863,6 +3863,7 @@ 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 7c65652..e102267 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; @@ -518,6 +531,8 @@ 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; @@ -974,6 +989,9 @@ 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)); @@ -1106,6 +1124,8 @@ 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; } -- 1.9.3
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