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Date: Thu, 5 Nov 2015 14:59:42 +0000
From: 平松雅巳 / HIRAMATU，MASAMI
<masami.hiramatsu.pt@...achi.com>
To: "'Namhyung Kim'" <namhyung@...nel.org>,
Tom Zanussi <tom.zanussi@...ux.intel.com>
CC: "rostedt@...dmis.org" <rostedt@...dmis.org>,
"daniel.wagner@...-carit.de" <daniel.wagner@...-carit.de>,
"josh@...htriplett.org" <josh@...htriplett.org>,
"andi@...stfloor.org" <andi@...stfloor.org>,
"mathieu.desnoyers@...icios.com" <mathieu.desnoyers@...icios.com>,
"peterz@...radead.org" <peterz@...radead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 00/28] tracing: 'hist' triggers
From: Namhyung Kim [mailto:namhyung@...il.com] On Behalf Of Namhyung Kim
>
>Hi Tom,
>
>I implemented 'log2' modifier on top of your v11 patchset. Could you
>please take a look at this?
Ah, this seems very useful :)
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
--
Masami
>
>
>
>From 5fc74778b9af5e4e121a0563fb8e54e8f495ca29 Mon Sep 17 00:00:00 2001
>From: Namhyung Kim <namhyung@...nel.org>
>Date: Thu, 5 Nov 2015 23:34:05 +0900
>Subject: [PATCH] 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
>
>Cc: Tom Zanussi <tom.zanussi@...ux.intel.com>
>Cc: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
>Signed-off-by: Namhyung Kim <namhyung@...nel.org>
>---
> kernel/trace/trace.c | 1 +
> kernel/trace/trace_events_hist.c | 18 ++++++++++++++++++
> 2 files changed, 19 insertions(+)
>
>diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
>index 74f95745acbc..542486468707 100644
>--- a/kernel/trace/trace.c
>+++ b/kernel/trace/trace.c
>@@ -3837,6 +3837,7 @@ 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 b040ebefcd64..20a17fdb3fe6 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)\
> { \
>@@ -103,6 +110,7 @@ enum hist_field_flags {
> HIST_FIELD_EXECNAME = 64,
> HIST_FIELD_SYSCALL = 128,
> HIST_FIELD_STACKTRACE = 256,
>+ HIST_FIELD_LOG2 = 512,
> };
>
> struct hist_trigger_attrs {
>@@ -349,6 +357,11 @@ static struct hist_field *create_hist_field(struct ftrace_event_field *field,
> goto out;
> }
>
>+ if (flags & HIST_FIELD_LOG2) {
>+ hist_field->fn = hist_field_log2;
>+ goto out;
>+ }
>+
> if (is_string_field(field)) {
> flags |= HIST_FIELD_STRING;
>
>@@ -500,6 +513,8 @@ static int create_key_field(struct hist_trigger_data *hist_data,
> flags |= HIST_FIELD_EXECNAME;
> else if (!strcmp(field_str, "syscall"))
> flags |= HIST_FIELD_SYSCALL;
>+ else if (!strcmp(field_str, "log2"))
>+ flags |= HIST_FIELD_LOG2;
> else {
> ret = -EINVAL;
> goto out;
>@@ -942,6 +957,9 @@ hist_trigger_entry_print(struct seq_file *m,
> key + key_field->offset,
> HIST_STACKTRACE_DEPTH);
> multiline = true;
>+ } else if (key_field->flags & HIST_FIELD_LOG2) {
>+ seq_printf(m, "%s: ~ 2^%-2llu", key_field->field->name,
>+ *(u64 *)(key + key_field->offset));
> } else if (key_field->flags & HIST_FIELD_STRING) {
> seq_printf(m, "%s: %-50s", key_field->field->name,
> (char *)(key + key_field->offset));
>--
>2.6.2
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