[PATCHSET 0/4] perf diff: Introduce delta-abs compute method (v2)

[PATCHSET 0/4] perf diff: Introduce delta-abs compute method (v2)

[Namhyung Kim]

Hello,

This patchset adds 'delta-abs' compute method to -c/--compute option.
The 'delta-abs' is same as 'delta' but shows entries with bigger
absolute delta first instead of sorting numerically.  This is only
useful together with -o option.

 * v2 changes
  - rebase onto acme/perf/core
  - change default option to '-o 1 -c delta-abs'


Below is default output (-c delta):

  $ perf diff -o 1 -c delta | grep -v ^# | head
    42.22%   +4.97%  [kernel.kallsyms]  [k] cfb_imageblit
     0.62%   +1.23%  [kernel.kallsyms]  [k] mutex_lock
             +1.15%  [kernel.kallsyms]  [k] copy_user_generic_string
     2.40%   +0.95%  [kernel.kallsyms]  [k] bit_putcs
     0.31%   +0.79%  [kernel.kallsyms]  [k] link_path_walk
             +0.64%  [kernel.kallsyms]  [k] kmem_cache_alloc
     0.00%   +0.57%  [kernel.kallsyms]  [k] __rcu_read_unlock
             +0.45%  [kernel.kallsyms]  [k] alloc_set_pte
     0.16%   +0.45%  [kernel.kallsyms]  [k] menu_select
             +0.41%  ld-2.24.so         [.] do_lookup_x

Now with 'delta-abs' it shows entries have bigger delta value either
positive or negative.

  $ perf diff -o 1 -c delta-abs | grep -v ^# | head
    42.22%   +4.97%  [kernel.kallsyms]  [k] cfb_imageblit
    12.72%   -3.01%  [kernel.kallsyms]  [k] intel_idle
     9.72%   -1.31%  [unknown]          [.] 0x0000000000411343
     0.62%   +1.23%  [kernel.kallsyms]  [k] mutex_lock
             +1.15%  [kernel.kallsyms]  [k] copy_user_generic_string
     2.40%   +0.95%  [kernel.kallsyms]  [k] bit_putcs
     0.31%   +0.79%  [kernel.kallsyms]  [k] link_path_walk
     1.35%   -0.71%  [kernel.kallsyms]  [k] smp_call_function_single
             +0.64%  [kernel.kallsyms]  [k] kmem_cache_alloc
     0.00%   +0.57%  [kernel.kallsyms]  [k] __rcu_read_unlock

The patch 2 and 3 are to add config options to control the default
behavior of perf diff command.  And patch 4 changes the default setting.

The code is avaiable at 'perf/diff-delta-abs-v2' branch in

  git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git

Thanks,
Namhyung


Namhyung Kim (4):
  perf diff: Add 'delta-abs' compute method
  perf diff: Add diff.order config option
  perf diff: Add diff.compute config option
  perf diff: Change default setting to "delta-abs"

 tools/perf/Documentation/perf-config.txt | 12 +++++
 tools/perf/Documentation/perf-diff.txt   | 15 ++++--
 tools/perf/builtin-diff.c                | 78 ++++++++++++++++++++++++++++++--
 3 files changed, 98 insertions(+), 7 deletions(-)

-- 
2.11.0

[PATCH v2 1/4] perf diff: Add 'delta-abs' compute method

[Namhyung Kim]

The 'delta-abs' compute method is same as 'delta' but shows entries with
bigger absolute delta first instead of sorting numerically.  This is
only useful together with -o option.

Below is default output (-c delta):

  $ perf diff -o 1 -c delta | grep -v ^# | head
    42.22%   +4.97%  [kernel.kallsyms]  [k] cfb_imageblit
     0.62%   +1.23%  [kernel.kallsyms]  [k] mutex_lock
             +1.15%  [kernel.kallsyms]  [k] copy_user_generic_string
     2.40%   +0.95%  [kernel.kallsyms]  [k] bit_putcs
     0.31%   +0.79%  [kernel.kallsyms]  [k] link_path_walk
             +0.64%  [kernel.kallsyms]  [k] kmem_cache_alloc
     0.00%   +0.57%  [kernel.kallsyms]  [k] __rcu_read_unlock
             +0.45%  [kernel.kallsyms]  [k] alloc_set_pte
     0.16%   +0.45%  [kernel.kallsyms]  [k] menu_select
             +0.41%  ld-2.24.so         [.] do_lookup_x

Now with 'delta-abs' it shows entries have bigger delta value either
positive or negative.

  $ perf diff -o 1 -c delta-abs | grep -v ^# | head
    42.22%   +4.97%  [kernel.kallsyms]  [k] cfb_imageblit
    12.72%   -3.01%  [kernel.kallsyms]  [k] intel_idle
     9.72%   -1.31%  [unknown]          [.] 0x0000000000411343
     0.62%   +1.23%  [kernel.kallsyms]  [k] mutex_lock
     2.40%   +0.95%  [kernel.kallsyms]  [k] bit_putcs
     0.31%   +0.79%  [kernel.kallsyms]  [k] link_path_walk
     1.35%   -0.71%  [kernel.kallsyms]  [k] smp_call_function_single
     0.00%   +0.57%  [kernel.kallsyms]  [k] __rcu_read_unlock
     0.16%   +0.45%  [kernel.kallsyms]  [k] menu_select
     0.72%   -0.44%  [kernel.kallsyms]  [k] lookup_fast

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/Documentation/perf-diff.txt |  6 ++++-
 tools/perf/builtin-diff.c              | 46 ++++++++++++++++++++++++++++++++--
 2 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index 3e9490b9c533..af80284cd2f6 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -86,7 +86,7 @@ OPTIONS
 
 -c::
 --compute::
-        Differential computation selection - delta,ratio,wdiff (default is delta).
+        Differential computation selection - delta,ratio,wdiff,delta-abs (default is delta).
         See COMPARISON METHODS section for more info.
 
 -p::
@@ -181,6 +181,10 @@ delta
     relative to how entries are filtered.  Use --percentage=absolute to
     prevent such fluctuation.
 
+delta-abs
+~~~~~~~~~
+Same as 'delta` method, but sort the result with the absolute values.
+
 ratio
 ~~~~~
 If specified the 'Ratio' column is displayed with value 'r' computed as:
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 933aeec46f4a..781c9e60bd21 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -30,6 +30,7 @@ enum {
 	PERF_HPP_DIFF__RATIO,
 	PERF_HPP_DIFF__WEIGHTED_DIFF,
 	PERF_HPP_DIFF__FORMULA,
+	PERF_HPP_DIFF__DELTA_ABS,
 
 	PERF_HPP_DIFF__MAX_INDEX
 };
@@ -73,11 +74,13 @@ enum {
 	COMPUTE_DELTA,
 	COMPUTE_RATIO,
 	COMPUTE_WEIGHTED_DIFF,
+	COMPUTE_DELTA_ABS,
 	COMPUTE_MAX,
 };
 
 const char *compute_names[COMPUTE_MAX] = {
 	[COMPUTE_DELTA] = "delta",
+	[COMPUTE_DELTA_ABS] = "delta-abs",
 	[COMPUTE_RATIO] = "ratio",
 	[COMPUTE_WEIGHTED_DIFF] = "wdiff",
 };
@@ -86,6 +89,7 @@ static int compute;
 
 static int compute_2_hpp[COMPUTE_MAX] = {
 	[COMPUTE_DELTA]		= PERF_HPP_DIFF__DELTA,
+	[COMPUTE_DELTA_ABS]	= PERF_HPP_DIFF__DELTA_ABS,
 	[COMPUTE_RATIO]		= PERF_HPP_DIFF__RATIO,
 	[COMPUTE_WEIGHTED_DIFF]	= PERF_HPP_DIFF__WEIGHTED_DIFF,
 };
@@ -111,6 +115,10 @@ static struct header_column {
 		.name  = "Delta",
 		.width = 7,
 	},
+	[PERF_HPP_DIFF__DELTA_ABS] = {
+		.name  = "Delta Abs",
+		.width = 7,
+	},
 	[PERF_HPP_DIFF__RATIO] = {
 		.name  = "Ratio",
 		.width = 14,
@@ -298,6 +306,7 @@ static int formula_fprintf(struct hist_entry *he, struct hist_entry *pair,
 {
 	switch (compute) {
 	case COMPUTE_DELTA:
+	case COMPUTE_DELTA_ABS:
 		return formula_delta(he, pair, buf, size);
 	case COMPUTE_RATIO:
 		return formula_ratio(he, pair, buf, size);
@@ -461,6 +470,7 @@ static void hists__precompute(struct hists *hists)
 
 			switch (compute) {
 			case COMPUTE_DELTA:
+			case COMPUTE_DELTA_ABS:
 				compute_delta(he, pair);
 				break;
 			case COMPUTE_RATIO:
@@ -498,6 +508,13 @@ __hist_entry__cmp_compute(struct hist_entry *left, struct hist_entry *right,
 
 		return cmp_doubles(l, r);
 	}
+	case COMPUTE_DELTA_ABS:
+	{
+		double l = fabs(left->diff.period_ratio_delta);
+		double r = fabs(right->diff.period_ratio_delta);
+
+		return cmp_doubles(l, r);
+	}
 	case COMPUTE_RATIO:
 	{
 		double l = left->diff.period_ratio;
@@ -564,7 +581,7 @@ hist_entry__cmp_compute_idx(struct hist_entry *left, struct hist_entry *right,
 	if (!p_left || !p_right)
 		return p_left ? -1 : 1;
 
-	if (c != COMPUTE_DELTA) {
+	if (c != COMPUTE_DELTA && c != COMPUTE_DELTA_ABS) {
 		/*
 		 * The delta can be computed without the baseline, but
 		 * others are not.  Put those entries which have no
@@ -607,6 +624,15 @@ hist_entry__cmp_delta(struct perf_hpp_fmt *fmt,
 }
 
 static int64_t
+hist_entry__cmp_delta_abs(struct perf_hpp_fmt *fmt,
+		      struct hist_entry *left, struct hist_entry *right)
+{
+	struct data__file *d = fmt_to_data_file(fmt);
+
+	return hist_entry__cmp_compute(right, left, COMPUTE_DELTA_ABS, d->idx);
+}
+
+static int64_t
 hist_entry__cmp_ratio(struct perf_hpp_fmt *fmt,
 		      struct hist_entry *left, struct hist_entry *right)
 {
@@ -633,6 +659,14 @@ hist_entry__cmp_delta_idx(struct perf_hpp_fmt *fmt __maybe_unused,
 }
 
 static int64_t
+hist_entry__cmp_delta_abs_idx(struct perf_hpp_fmt *fmt __maybe_unused,
+			      struct hist_entry *left, struct hist_entry *right)
+{
+	return hist_entry__cmp_compute_idx(right, left, COMPUTE_DELTA_ABS,
+					   sort_compute);
+}
+
+static int64_t
 hist_entry__cmp_ratio_idx(struct perf_hpp_fmt *fmt __maybe_unused,
 			  struct hist_entry *left, struct hist_entry *right)
 {
@@ -775,7 +809,7 @@ static const struct option options[] = {
 	OPT_BOOLEAN('b', "baseline-only", &show_baseline_only,
 		    "Show only items with match in baseline"),
 	OPT_CALLBACK('c', "compute", &compute,
-		     "delta,ratio,wdiff:w1,w2 (default delta)",
+		     "delta,delta-abs,ratio,wdiff:w1,w2 (default delta)",
 		     "Entries differential computation selection",
 		     setup_compute),
 	OPT_BOOLEAN('p', "period", &show_period,
@@ -945,6 +979,7 @@ hpp__entry_pair(struct hist_entry *he, struct hist_entry *pair,
 
 	switch (idx) {
 	case PERF_HPP_DIFF__DELTA:
+	case PERF_HPP_DIFF__DELTA_ABS:
 		if (pair->diff.computed)
 			diff = pair->diff.period_ratio_delta;
 		else
@@ -1118,6 +1153,10 @@ static void data__hpp_register(struct data__file *d, int idx)
 		fmt->color = hpp__color_wdiff;
 		fmt->sort  = hist_entry__cmp_wdiff;
 		break;
+	case PERF_HPP_DIFF__DELTA_ABS:
+		fmt->color = hpp__color_delta;
+		fmt->sort  = hist_entry__cmp_delta_abs;
+		break;
 	default:
 		fmt->sort  = hist_entry__cmp_nop;
 		break;
@@ -1195,6 +1234,9 @@ static int ui_init(void)
 	case COMPUTE_WEIGHTED_DIFF:
 		fmt->sort = hist_entry__cmp_wdiff_idx;
 		break;
+	case COMPUTE_DELTA_ABS:
+		fmt->sort = hist_entry__cmp_delta_abs_idx;
+		break;
 	default:
 		BUG_ON(1);
 	}
-- 
2.11.0

[PATCH v2 2/4] perf diff: Add diff.order config option

[Namhyung Kim]

In many cases, I need to look at differences between two data so I often
used the -o option to sort the result base on the difference first.
It'd be nice to have a config option to set it by default.

The diff.order config option is to set the default value of -o/--order
option.

Cc: Taeung Song <treeze.taeung@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/Documentation/perf-config.txt |  7 +++++++
 tools/perf/Documentation/perf-diff.txt   |  6 +++++-
 tools/perf/builtin-diff.c                | 14 ++++++++++++++
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt
index 9365b75fd04f..5b54d47ef713 100644
--- a/tools/perf/Documentation/perf-config.txt
+++ b/tools/perf/Documentation/perf-config.txt
@@ -498,6 +498,13 @@ Variables
 		But if this option is 'no-cache', it will not update the build-id cache.
 		'skip' skips post-processing and does not update the cache.
 
+diff.*::
+	diff.order::
+		This option sets the number of column to sort the result.
+		Default is 0 which means sorting by baseline.
+		Setting it to 1 will sort the result by delta (or other
+		compute method selected).
+
 SEE ALSO
 --------
 linkperf:perf[1]
diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index af80284cd2f6..6ba3bf582d79 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -99,7 +99,11 @@ OPTIONS
 
 -o::
 --order::
-       Specify compute sorting column number.
+       Specify compute sorting column number.  0 means sorting by baseline
+       overhead (default) and 1 means sorting by computed value of column 1
+       (data from the first file other base baseline).  Values more than 1
+       can be used only if enough data files are provided.
+       Default value can be set using diff.order config option.
 
 --percentage::
 	Determine how to display the overhead percentage of filtered entries.
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 781c9e60bd21..181ff996e039 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -17,6 +17,7 @@
 #include "util/symbol.h"
 #include "util/util.h"
 #include "util/data.h"
+#include "util/config.h"
 
 #include <stdlib.h>
 #include <math.h>
@@ -1291,6 +1292,17 @@ static int data_init(int argc, const char **argv)
 	return 0;
 }
 
+static int diff__config(const char *var, const char *value,
+			void *cb __maybe_unused)
+{
+	if (!strcmp(var, "diff.order")) {
+		sort_compute = perf_config_int(var, value);
+		return 0;
+	}
+
+	return 0;
+}
+
 int cmd_diff(int argc, const char **argv, const char *prefix __maybe_unused)
 {
 	int ret = hists__init();
@@ -1298,6 +1310,8 @@ int cmd_diff(int argc, const char **argv, const char *prefix __maybe_unused)
 	if (ret < 0)
 		return ret;
 
+	perf_config(diff__config, NULL);
+
 	argc = parse_options(argc, argv, options, diff_usage, 0);
 
 	if (symbol__init(NULL) < 0)
-- 
2.11.0

[PATCH v2 3/4] perf diff: Add diff.compute config option

[Namhyung Kim]

The diff.compute config variable is to set the default compute method of
perf diff command (-c option).  Possible values 'delta' (default),
'delta-abs', 'ratio' and 'wdiff'.

Cc: Taeung Song <treeze.taeung@gmail.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/Documentation/perf-config.txt |  5 +++++
 tools/perf/Documentation/perf-diff.txt   |  5 +++--
 tools/perf/builtin-diff.c                | 16 +++++++++++++++-
 3 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt
index 5b54d47ef713..f2d758dc1edc 100644
--- a/tools/perf/Documentation/perf-config.txt
+++ b/tools/perf/Documentation/perf-config.txt
@@ -505,6 +505,11 @@ Variables
 		Setting it to 1 will sort the result by delta (or other
 		compute method selected).
 
+	diff.compute::
+		This options sets the method of computing diff result.
+		Possible values are 'delta', 'delta-abs', 'ratio' and
+		'wdiff'.  Default is 'delta'.
+
 SEE ALSO
 --------
 linkperf:perf[1]
diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index 6ba3bf582d79..70f490408262 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -86,8 +86,9 @@ OPTIONS
 
 -c::
 --compute::
-        Differential computation selection - delta,ratio,wdiff,delta-abs (default is delta).
-        See COMPARISON METHODS section for more info.
+        Differential computation selection - delta,ratio,wdiff,delta-abs
+	(default is delta).  Default can be changed using diff.compute
+	config option.  See COMPARISON METHODS section for more info.
 
 -p::
 --period::
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 181ff996e039..4b4004d41c6a 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -86,7 +86,7 @@ const char *compute_names[COMPUTE_MAX] = {
 	[COMPUTE_WEIGHTED_DIFF] = "wdiff",
 };
 
-static int compute;
+static int compute = COMPUTE_DELTA;
 
 static int compute_2_hpp[COMPUTE_MAX] = {
 	[COMPUTE_DELTA]		= PERF_HPP_DIFF__DELTA,
@@ -1299,6 +1299,20 @@ static int diff__config(const char *var, const char *value,
 		sort_compute = perf_config_int(var, value);
 		return 0;
 	}
+	if (!strcmp(var, "diff.compute")) {
+		if (!strcmp(value, "delta"))
+			compute = COMPUTE_DELTA;
+		else if (!strcmp(value, "delta-abs"))
+			compute = COMPUTE_DELTA_ABS;
+		else if (!strcmp(value, "ratio"))
+			compute = COMPUTE_RATIO;
+		else if (!strcmp(value, "wdiff"))
+			compute = COMPUTE_WEIGHTED_DIFF;
+		else {
+			pr_err("Invalid compute method: %s\n", value);
+			return -1;
+		}
+	}
 
 	return 0;
 }
-- 
2.11.0

[PATCH v2 4/4] perf diff: Change default setting to "delta-abs"

[Namhyung Kim]

The "delta-abs" compute method will show most changed entries on top.
So users can easily see how much effect between the data.  To see
original-style (sorted by baseline) use -o 0 option.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/builtin-diff.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 4b4004d41c6a..27300f2c665b 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -66,7 +66,7 @@ static bool force;
 static bool show_period;
 static bool show_formula;
 static bool show_baseline_only;
-static unsigned int sort_compute;
+static unsigned int sort_compute = 1;
 
 static s64 compute_wdiff_w1;
 static s64 compute_wdiff_w2;
@@ -86,7 +86,7 @@ const char *compute_names[COMPUTE_MAX] = {
 	[COMPUTE_WEIGHTED_DIFF] = "wdiff",
 };
 
-static int compute = COMPUTE_DELTA;
+static int compute = COMPUTE_DELTA_ABS;
 
 static int compute_2_hpp[COMPUTE_MAX] = {
 	[COMPUTE_DELTA]		= PERF_HPP_DIFF__DELTA,
-- 
2.11.0

Re: [PATCHSET 0/4] perf diff: Introduce delta-abs compute method (v2)

[Ingo Molnar]

* Namhyung Kim <namhyung@kernel.org> wrote:

> Hello,
> 
> This patchset adds 'delta-abs' compute method to -c/--compute option.
> The 'delta-abs' is same as 'delta' but shows entries with bigger
> absolute delta first instead of sorting numerically.  This is only
> useful together with -o option.
> 
>  * v2 changes
>   - rebase onto acme/perf/core
>   - change default option to '-o 1 -c delta-abs'
> 
> 
> Below is default output (-c delta):
> 
>   $ perf diff -o 1 -c delta | grep -v ^# | head
>     42.22%   +4.97%  [kernel.kallsyms]  [k] cfb_imageblit
>      0.62%   +1.23%  [kernel.kallsyms]  [k] mutex_lock
>              +1.15%  [kernel.kallsyms]  [k] copy_user_generic_string
>      2.40%   +0.95%  [kernel.kallsyms]  [k] bit_putcs
>      0.31%   +0.79%  [kernel.kallsyms]  [k] link_path_walk
>              +0.64%  [kernel.kallsyms]  [k] kmem_cache_alloc
>      0.00%   +0.57%  [kernel.kallsyms]  [k] __rcu_read_unlock
>              +0.45%  [kernel.kallsyms]  [k] alloc_set_pte
>      0.16%   +0.45%  [kernel.kallsyms]  [k] menu_select
>              +0.41%  ld-2.24.so         [.] do_lookup_x
> 
> Now with 'delta-abs' it shows entries have bigger delta value either
> positive or negative.
> 
>   $ perf diff -o 1 -c delta-abs | grep -v ^# | head
>     42.22%   +4.97%  [kernel.kallsyms]  [k] cfb_imageblit
>     12.72%   -3.01%  [kernel.kallsyms]  [k] intel_idle
>      9.72%   -1.31%  [unknown]          [.] 0x0000000000411343
>      0.62%   +1.23%  [kernel.kallsyms]  [k] mutex_lock
>              +1.15%  [kernel.kallsyms]  [k] copy_user_generic_string
>      2.40%   +0.95%  [kernel.kallsyms]  [k] bit_putcs
>      0.31%   +0.79%  [kernel.kallsyms]  [k] link_path_walk
>      1.35%   -0.71%  [kernel.kallsyms]  [k] smp_call_function_single
>              +0.64%  [kernel.kallsyms]  [k] kmem_cache_alloc
>      0.00%   +0.57%  [kernel.kallsyms]  [k] __rcu_read_unlock

Nice!

BTW., to me the second output looks a lot more intuitive and useful than the 
default one.

Would it be possible to flip over the default to the 'most useful' options, and 
see whether anyone complains?

Thanks,

	Ingo

Re: [PATCHSET 0/4] perf diff: Introduce delta-abs compute method (v2)

[Namhyung Kim]

Hi Ingo,

On Fri, Feb 10, 2017 at 08:41:11AM +0100, Ingo Molnar wrote:
> 
> * Namhyung Kim <namhyung@kernel.org> wrote:
> 
> > Hello,
> > 
> > This patchset adds 'delta-abs' compute method to -c/--compute option.
> > The 'delta-abs' is same as 'delta' but shows entries with bigger
> > absolute delta first instead of sorting numerically.  This is only
> > useful together with -o option.
> > 
> >  * v2 changes
> >   - rebase onto acme/perf/core
> >   - change default option to '-o 1 -c delta-abs'
> > 
> > 
> > Below is default output (-c delta):
> > 
> >   $ perf diff -o 1 -c delta | grep -v ^# | head
> >     42.22%   +4.97%  [kernel.kallsyms]  [k] cfb_imageblit
> >      0.62%   +1.23%  [kernel.kallsyms]  [k] mutex_lock
> >              +1.15%  [kernel.kallsyms]  [k] copy_user_generic_string
> >      2.40%   +0.95%  [kernel.kallsyms]  [k] bit_putcs
> >      0.31%   +0.79%  [kernel.kallsyms]  [k] link_path_walk
> >              +0.64%  [kernel.kallsyms]  [k] kmem_cache_alloc
> >      0.00%   +0.57%  [kernel.kallsyms]  [k] __rcu_read_unlock
> >              +0.45%  [kernel.kallsyms]  [k] alloc_set_pte
> >      0.16%   +0.45%  [kernel.kallsyms]  [k] menu_select
> >              +0.41%  ld-2.24.so         [.] do_lookup_x
> > 
> > Now with 'delta-abs' it shows entries have bigger delta value either
> > positive or negative.
> > 
> >   $ perf diff -o 1 -c delta-abs | grep -v ^# | head
> >     42.22%   +4.97%  [kernel.kallsyms]  [k] cfb_imageblit
> >     12.72%   -3.01%  [kernel.kallsyms]  [k] intel_idle
> >      9.72%   -1.31%  [unknown]          [.] 0x0000000000411343
> >      0.62%   +1.23%  [kernel.kallsyms]  [k] mutex_lock
> >              +1.15%  [kernel.kallsyms]  [k] copy_user_generic_string
> >      2.40%   +0.95%  [kernel.kallsyms]  [k] bit_putcs
> >      0.31%   +0.79%  [kernel.kallsyms]  [k] link_path_walk
> >      1.35%   -0.71%  [kernel.kallsyms]  [k] smp_call_function_single
> >              +0.64%  [kernel.kallsyms]  [k] kmem_cache_alloc
> >      0.00%   +0.57%  [kernel.kallsyms]  [k] __rcu_read_unlock
> 
> Nice!
> 
> BTW., to me the second output looks a lot more intuitive and useful than the 
> default one.

Thanks!

> 
> Would it be possible to flip over the default to the 'most useful' options, and 
> see whether anyone complains?

The patch 4 makes it default.

By the way, the current default (sort by baseline) looks like below:

  $ perf diff | grep -v ^# | head
    42.22%   +4.97%  [kernel.kallsyms]  [k] cfb_imageblit
    12.72%   -3.01%  [kernel.kallsyms]  [k] intel_idle
     9.72%   -1.31%  [unknown]          [.] 0x0000000000411343
     2.40%   +0.95%  [kernel.kallsyms]  [k] bit_putcs
     1.35%   -0.71%  [kernel.kallsyms]  [k] smp_call_function_single
     0.62%   +1.23%  [kernel.kallsyms]  [k] mutex_lock
     0.31%   +0.79%  [kernel.kallsyms]  [k] link_path_walk
     0.16%   +0.45%  [kernel.kallsyms]  [k] menu_select
     0.00%   +0.57%  [kernel.kallsyms]  [k] __rcu_read_unlock

While this example doesn't show much difference, it could be..

Thanks,
Namhyung

Re: [PATCHSET 0/4] perf diff: Introduce delta-abs compute method (v2)

[Ingo Molnar]

* Namhyung Kim <namhyung@kernel.org> wrote:

> > Would it be possible to flip over the default to the 'most useful' options, and 
> > see whether anyone complains?
> 
> The patch 4 makes it default.

/me must be blind!

Yes, looks really nice that way.

Thanks,

	Ingo

[PATCH v2.1 4/4] perf diff: Change default setting to "delta-abs"

[Namhyung Kim]

The "delta-abs" compute method will show most changed entries on top.
So users can easily see how much effect between the data.  Note that it
also changes the default of -o option to 1 in order to apply the compute
method.  To see original-style (sorted by baseline) use -o 0 option.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/Documentation/perf-diff.txt | 4 ++--
 tools/perf/builtin-diff.c              | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index 70f490408262..c0aaad5af2a8 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -87,7 +87,7 @@ OPTIONS
 -c::
 --compute::
         Differential computation selection - delta,ratio,wdiff,delta-abs
-	(default is delta).  Default can be changed using diff.compute
+	(default is delta-abs).  Default can be changed using diff.compute
 	config option.  See COMPARISON METHODS section for more info.
 
 -p::
@@ -101,7 +101,7 @@ OPTIONS
 -o::
 --order::
        Specify compute sorting column number.  0 means sorting by baseline
-       overhead (default) and 1 means sorting by computed value of column 1
+       overhead and 1 (default) means sorting by computed value of column 1
        (data from the first file other base baseline).  Values more than 1
        can be used only if enough data files are provided.
        Default value can be set using diff.order config option.
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 4b4004d41c6a..45bfbee647a7 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -66,7 +66,7 @@ static bool force;
 static bool show_period;
 static bool show_formula;
 static bool show_baseline_only;
-static unsigned int sort_compute;
+static unsigned int sort_compute = 1;
 
 static s64 compute_wdiff_w1;
 static s64 compute_wdiff_w2;
@@ -86,7 +86,7 @@ const char *compute_names[COMPUTE_MAX] = {
 	[COMPUTE_WEIGHTED_DIFF] = "wdiff",
 };
 
-static int compute = COMPUTE_DELTA;
+static int compute = COMPUTE_DELTA_ABS;
 
 static int compute_2_hpp[COMPUTE_MAX] = {
 	[COMPUTE_DELTA]		= PERF_HPP_DIFF__DELTA,
@@ -810,7 +810,7 @@ static const struct option options[] = {
 	OPT_BOOLEAN('b', "baseline-only", &show_baseline_only,
 		    "Show only items with match in baseline"),
 	OPT_CALLBACK('c', "compute", &compute,
-		     "delta,delta-abs,ratio,wdiff:w1,w2 (default delta)",
+		     "delta,delta-abs,ratio,wdiff:w1,w2 (default delta-abs)",
 		     "Entries differential computation selection",
 		     setup_compute),
 	OPT_BOOLEAN('p', "period", &show_period,
-- 
2.11.0

[tip:perf/core] perf diff: Add 'delta-abs' compute method

[tip-bot for Namhyung Kim]

Commit-ID:  a1668c25a8e1b53d00b2997ef5bc5e25c7a77235
Gitweb:     http://git.kernel.org/tip/a1668c25a8e1b53d00b2997ef5bc5e25c7a77235
Author:     Namhyung Kim <namhyung@kernel.org>
AuthorDate: Fri, 10 Feb 2017 16:36:11 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 13 Feb 2017 14:29:36 -0300

perf diff: Add 'delta-abs' compute method

The 'delta-abs' compute method is same as 'delta' but shows entries with
bigger absolute delta first instead of sorting numerically.  This is
only useful together with -o option.

Below is default output (-c delta):

  $ perf diff -o 1 -c delta | grep -v ^# | head
    42.22%   +4.97%  [kernel.kallsyms]  [k] cfb_imageblit
     0.62%   +1.23%  [kernel.kallsyms]  [k] mutex_lock
             +1.15%  [kernel.kallsyms]  [k] copy_user_generic_string
     2.40%   +0.95%  [kernel.kallsyms]  [k] bit_putcs
     0.31%   +0.79%  [kernel.kallsyms]  [k] link_path_walk
             +0.64%  [kernel.kallsyms]  [k] kmem_cache_alloc
     0.00%   +0.57%  [kernel.kallsyms]  [k] __rcu_read_unlock
             +0.45%  [kernel.kallsyms]  [k] alloc_set_pte
     0.16%   +0.45%  [kernel.kallsyms]  [k] menu_select
             +0.41%  ld-2.24.so         [.] do_lookup_x

Now with 'delta-abs' it shows entries have bigger delta value either
positive or negative.

  $ perf diff -o 1 -c delta-abs | grep -v ^# | head
    42.22%   +4.97%  [kernel.kallsyms]  [k] cfb_imageblit
    12.72%   -3.01%  [kernel.kallsyms]  [k] intel_idle
     9.72%   -1.31%  [unknown]          [.] 0x0000000000411343
     0.62%   +1.23%  [kernel.kallsyms]  [k] mutex_lock
     2.40%   +0.95%  [kernel.kallsyms]  [k] bit_putcs
     0.31%   +0.79%  [kernel.kallsyms]  [k] link_path_walk
     1.35%   -0.71%  [kernel.kallsyms]  [k] smp_call_function_single
     0.00%   +0.57%  [kernel.kallsyms]  [k] __rcu_read_unlock
     0.16%   +0.45%  [kernel.kallsyms]  [k] menu_select
     0.72%   -0.44%  [kernel.kallsyms]  [k] lookup_fast

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20170210073614.24584-2-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/Documentation/perf-diff.txt |  6 ++++-
 tools/perf/builtin-diff.c              | 46 ++++++++++++++++++++++++++++++++--
 2 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index 3e9490b..af80284 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -86,7 +86,7 @@ OPTIONS
 
 -c::
 --compute::
-        Differential computation selection - delta,ratio,wdiff (default is delta).
+        Differential computation selection - delta,ratio,wdiff,delta-abs (default is delta).
         See COMPARISON METHODS section for more info.
 
 -p::
@@ -181,6 +181,10 @@ with:
     relative to how entries are filtered.  Use --percentage=absolute to
     prevent such fluctuation.
 
+delta-abs
+~~~~~~~~~
+Same as 'delta` method, but sort the result with the absolute values.
+
 ratio
 ~~~~~
 If specified the 'Ratio' column is displayed with value 'r' computed as:
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 933aeec..781c9e6 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -30,6 +30,7 @@ enum {
 	PERF_HPP_DIFF__RATIO,
 	PERF_HPP_DIFF__WEIGHTED_DIFF,
 	PERF_HPP_DIFF__FORMULA,
+	PERF_HPP_DIFF__DELTA_ABS,
 
 	PERF_HPP_DIFF__MAX_INDEX
 };
@@ -73,11 +74,13 @@ enum {
 	COMPUTE_DELTA,
 	COMPUTE_RATIO,
 	COMPUTE_WEIGHTED_DIFF,
+	COMPUTE_DELTA_ABS,
 	COMPUTE_MAX,
 };
 
 const char *compute_names[COMPUTE_MAX] = {
 	[COMPUTE_DELTA] = "delta",
+	[COMPUTE_DELTA_ABS] = "delta-abs",
 	[COMPUTE_RATIO] = "ratio",
 	[COMPUTE_WEIGHTED_DIFF] = "wdiff",
 };
@@ -86,6 +89,7 @@ static int compute;
 
 static int compute_2_hpp[COMPUTE_MAX] = {
 	[COMPUTE_DELTA]		= PERF_HPP_DIFF__DELTA,
+	[COMPUTE_DELTA_ABS]	= PERF_HPP_DIFF__DELTA_ABS,
 	[COMPUTE_RATIO]		= PERF_HPP_DIFF__RATIO,
 	[COMPUTE_WEIGHTED_DIFF]	= PERF_HPP_DIFF__WEIGHTED_DIFF,
 };
@@ -111,6 +115,10 @@ static struct header_column {
 		.name  = "Delta",
 		.width = 7,
 	},
+	[PERF_HPP_DIFF__DELTA_ABS] = {
+		.name  = "Delta Abs",
+		.width = 7,
+	},
 	[PERF_HPP_DIFF__RATIO] = {
 		.name  = "Ratio",
 		.width = 14,
@@ -298,6 +306,7 @@ static int formula_fprintf(struct hist_entry *he, struct hist_entry *pair,
 {
 	switch (compute) {
 	case COMPUTE_DELTA:
+	case COMPUTE_DELTA_ABS:
 		return formula_delta(he, pair, buf, size);
 	case COMPUTE_RATIO:
 		return formula_ratio(he, pair, buf, size);
@@ -461,6 +470,7 @@ static void hists__precompute(struct hists *hists)
 
 			switch (compute) {
 			case COMPUTE_DELTA:
+			case COMPUTE_DELTA_ABS:
 				compute_delta(he, pair);
 				break;
 			case COMPUTE_RATIO:
@@ -498,6 +508,13 @@ __hist_entry__cmp_compute(struct hist_entry *left, struct hist_entry *right,
 
 		return cmp_doubles(l, r);
 	}
+	case COMPUTE_DELTA_ABS:
+	{
+		double l = fabs(left->diff.period_ratio_delta);
+		double r = fabs(right->diff.period_ratio_delta);
+
+		return cmp_doubles(l, r);
+	}
 	case COMPUTE_RATIO:
 	{
 		double l = left->diff.period_ratio;
@@ -564,7 +581,7 @@ hist_entry__cmp_compute_idx(struct hist_entry *left, struct hist_entry *right,
 	if (!p_left || !p_right)
 		return p_left ? -1 : 1;
 
-	if (c != COMPUTE_DELTA) {
+	if (c != COMPUTE_DELTA && c != COMPUTE_DELTA_ABS) {
 		/*
 		 * The delta can be computed without the baseline, but
 		 * others are not.  Put those entries which have no
@@ -607,6 +624,15 @@ hist_entry__cmp_delta(struct perf_hpp_fmt *fmt,
 }
 
 static int64_t
+hist_entry__cmp_delta_abs(struct perf_hpp_fmt *fmt,
+		      struct hist_entry *left, struct hist_entry *right)
+{
+	struct data__file *d = fmt_to_data_file(fmt);
+
+	return hist_entry__cmp_compute(right, left, COMPUTE_DELTA_ABS, d->idx);
+}
+
+static int64_t
 hist_entry__cmp_ratio(struct perf_hpp_fmt *fmt,
 		      struct hist_entry *left, struct hist_entry *right)
 {
@@ -633,6 +659,14 @@ hist_entry__cmp_delta_idx(struct perf_hpp_fmt *fmt __maybe_unused,
 }
 
 static int64_t
+hist_entry__cmp_delta_abs_idx(struct perf_hpp_fmt *fmt __maybe_unused,
+			      struct hist_entry *left, struct hist_entry *right)
+{
+	return hist_entry__cmp_compute_idx(right, left, COMPUTE_DELTA_ABS,
+					   sort_compute);
+}
+
+static int64_t
 hist_entry__cmp_ratio_idx(struct perf_hpp_fmt *fmt __maybe_unused,
 			  struct hist_entry *left, struct hist_entry *right)
 {
@@ -775,7 +809,7 @@ static const struct option options[] = {
 	OPT_BOOLEAN('b', "baseline-only", &show_baseline_only,
 		    "Show only items with match in baseline"),
 	OPT_CALLBACK('c', "compute", &compute,
-		     "delta,ratio,wdiff:w1,w2 (default delta)",
+		     "delta,delta-abs,ratio,wdiff:w1,w2 (default delta)",
 		     "Entries differential computation selection",
 		     setup_compute),
 	OPT_BOOLEAN('p', "period", &show_period,
@@ -945,6 +979,7 @@ hpp__entry_pair(struct hist_entry *he, struct hist_entry *pair,
 
 	switch (idx) {
 	case PERF_HPP_DIFF__DELTA:
+	case PERF_HPP_DIFF__DELTA_ABS:
 		if (pair->diff.computed)
 			diff = pair->diff.period_ratio_delta;
 		else
@@ -1118,6 +1153,10 @@ static void data__hpp_register(struct data__file *d, int idx)
 		fmt->color = hpp__color_wdiff;
 		fmt->sort  = hist_entry__cmp_wdiff;
 		break;
+	case PERF_HPP_DIFF__DELTA_ABS:
+		fmt->color = hpp__color_delta;
+		fmt->sort  = hist_entry__cmp_delta_abs;
+		break;
 	default:
 		fmt->sort  = hist_entry__cmp_nop;
 		break;
@@ -1195,6 +1234,9 @@ static int ui_init(void)
 	case COMPUTE_WEIGHTED_DIFF:
 		fmt->sort = hist_entry__cmp_wdiff_idx;
 		break;
+	case COMPUTE_DELTA_ABS:
+		fmt->sort = hist_entry__cmp_delta_abs_idx;
+		break;
 	default:
 		BUG_ON(1);
 	}

[tip:perf/core] perf diff: Add diff.order config option

[tip-bot for Namhyung Kim]

Commit-ID:  d49dd15d69731589de4436a6dcfca59567320fdf
Gitweb:     http://git.kernel.org/tip/d49dd15d69731589de4436a6dcfca59567320fdf
Author:     Namhyung Kim <namhyung@kernel.org>
AuthorDate: Fri, 10 Feb 2017 16:36:12 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 13 Feb 2017 14:29:37 -0300

perf diff: Add diff.order config option

In many cases, I need to look at differences between two data so I often
used the -o option to sort the result base on the difference first.
It'd be nice to have a config option to set it by default.

The diff.order config option is to set the default value of -o/--order
option.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Taeung Song <treeze.taeung@gmail.com>
Link: http://lkml.kernel.org/r/20170210073614.24584-3-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/Documentation/perf-config.txt |  7 +++++++
 tools/perf/Documentation/perf-diff.txt   |  6 +++++-
 tools/perf/builtin-diff.c                | 14 ++++++++++++++
 3 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt
index 9365b75..49ab79d 100644
--- a/tools/perf/Documentation/perf-config.txt
+++ b/tools/perf/Documentation/perf-config.txt
@@ -498,6 +498,13 @@ record.*::
 		But if this option is 'no-cache', it will not update the build-id cache.
 		'skip' skips post-processing and does not update the cache.
 
+diff.*::
+	diff.order::
+		This option sets the number of columns to sort the result.
+		The default is 0, which means sorting by baseline.
+		Setting it to 1 will sort the result by delta (or other
+		compute method selected).
+
 SEE ALSO
 --------
 linkperf:perf[1]
diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index af80284..7c014c9 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -99,7 +99,11 @@ OPTIONS
 
 -o::
 --order::
-       Specify compute sorting column number.
+       Specify compute sorting column number.  0 means sorting by baseline
+       overhead (default) and 1 means sorting by computed value of column 1
+       (data from the first file other base baseline).  Values more than 1
+       can be used only if enough data files are provided.
+       The default value can be set using the diff.order config option.
 
 --percentage::
 	Determine how to display the overhead percentage of filtered entries.
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 781c9e6..181ff99 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -17,6 +17,7 @@
 #include "util/symbol.h"
 #include "util/util.h"
 #include "util/data.h"
+#include "util/config.h"
 
 #include <stdlib.h>
 #include <math.h>
@@ -1291,6 +1292,17 @@ static int data_init(int argc, const char **argv)
 	return 0;
 }
 
+static int diff__config(const char *var, const char *value,
+			void *cb __maybe_unused)
+{
+	if (!strcmp(var, "diff.order")) {
+		sort_compute = perf_config_int(var, value);
+		return 0;
+	}
+
+	return 0;
+}
+
 int cmd_diff(int argc, const char **argv, const char *prefix __maybe_unused)
 {
 	int ret = hists__init();
@@ -1298,6 +1310,8 @@ int cmd_diff(int argc, const char **argv, const char *prefix __maybe_unused)
 	if (ret < 0)
 		return ret;
 
+	perf_config(diff__config, NULL);
+
 	argc = parse_options(argc, argv, options, diff_usage, 0);
 
 	if (symbol__init(NULL) < 0)

[tip:perf/core] perf diff: Add diff.compute config option

[tip-bot for Namhyung Kim]

Commit-ID:  4b35994abe459f08f58b4b3855abf4ba80308680
Gitweb:     http://git.kernel.org/tip/4b35994abe459f08f58b4b3855abf4ba80308680
Author:     Namhyung Kim <namhyung@kernel.org>
AuthorDate: Fri, 10 Feb 2017 16:36:13 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 13 Feb 2017 14:29:37 -0300

perf diff: Add diff.compute config option

The diff.compute config variable is to set the default compute method of
perf diff command (-c option).  Possible values 'delta' (default),
'delta-abs', 'ratio' and 'wdiff'.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Taeung Song <treeze.taeung@gmail.com>
Link: http://lkml.kernel.org/r/20170210073614.24584-4-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/Documentation/perf-config.txt |  5 +++++
 tools/perf/Documentation/perf-diff.txt   |  5 +++--
 tools/perf/builtin-diff.c                | 16 +++++++++++++++-
 3 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt
index 49ab79d..5b4fff3 100644
--- a/tools/perf/Documentation/perf-config.txt
+++ b/tools/perf/Documentation/perf-config.txt
@@ -505,6 +505,11 @@ diff.*::
 		Setting it to 1 will sort the result by delta (or other
 		compute method selected).
 
+	diff.compute::
+		This options sets the method for computing the diff result.
+		Possible values are 'delta', 'delta-abs', 'ratio' and
+		'wdiff'.  Default is 'delta'.
+
 SEE ALSO
 --------
 linkperf:perf[1]
diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index 7c014c9..7391299 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -86,8 +86,9 @@ OPTIONS
 
 -c::
 --compute::
-        Differential computation selection - delta,ratio,wdiff,delta-abs (default is delta).
-        See COMPARISON METHODS section for more info.
+        Differential computation selection - delta, ratio, wdiff, delta-abs
+        (default is delta).  Default can be changed using diff.compute
+        config option.  See COMPARISON METHODS section for more info.
 
 -p::
 --period::
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 181ff99..e68cc76 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -86,7 +86,7 @@ const char *compute_names[COMPUTE_MAX] = {
 	[COMPUTE_WEIGHTED_DIFF] = "wdiff",
 };
 
-static int compute;
+static int compute = COMPUTE_DELTA;
 
 static int compute_2_hpp[COMPUTE_MAX] = {
 	[COMPUTE_DELTA]		= PERF_HPP_DIFF__DELTA,
@@ -1299,6 +1299,20 @@ static int diff__config(const char *var, const char *value,
 		sort_compute = perf_config_int(var, value);
 		return 0;
 	}
+	if (!strcmp(var, "diff.compute")) {
+		if (!strcmp(value, "delta")) {
+			compute = COMPUTE_DELTA;
+		} else if (!strcmp(value, "delta-abs")) {
+			compute = COMPUTE_DELTA_ABS;
+		} else if (!strcmp(value, "ratio")) {
+			compute = COMPUTE_RATIO;
+		} else if (!strcmp(value, "wdiff")) {
+			compute = COMPUTE_WEIGHTED_DIFF;
+		} else {
+			pr_err("Invalid compute method: %s\n", value);
+			return -1;
+		}
+	}
 
 	return 0;
 }

[tip:perf/core] perf diff: Change default setting to "delta-abs"

[tip-bot for Namhyung Kim]

Commit-ID:  be57b3fd218ad4a19725ac4bd53e67b2ede42a9d
Gitweb:     http://git.kernel.org/tip/be57b3fd218ad4a19725ac4bd53e67b2ede42a9d
Author:     Namhyung Kim <namhyung@kernel.org>
AuthorDate: Sat, 11 Feb 2017 01:18:56 +0900
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 13 Feb 2017 14:29:38 -0300

perf diff: Change default setting to "delta-abs"

The "delta-abs" compute method will show most changed entries on top.
So users can easily see how much effect between the data.  Note that it
also changes the default of -o option to 1 in order to apply the compute
method.  To see original-style (sorted by baseline) use -o 0 option.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20170210161856.18422-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/Documentation/perf-diff.txt | 4 ++--
 tools/perf/builtin-diff.c              | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index 7391299..66dbe3de 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -87,7 +87,7 @@ OPTIONS
 -c::
 --compute::
         Differential computation selection - delta, ratio, wdiff, delta-abs
-        (default is delta).  Default can be changed using diff.compute
+        (default is delta-abs).  Default can be changed using diff.compute
         config option.  See COMPARISON METHODS section for more info.
 
 -p::
@@ -101,7 +101,7 @@ OPTIONS
 -o::
 --order::
        Specify compute sorting column number.  0 means sorting by baseline
-       overhead (default) and 1 means sorting by computed value of column 1
+       overhead and 1 (default) means sorting by computed value of column 1
        (data from the first file other base baseline).  Values more than 1
        can be used only if enough data files are provided.
        The default value can be set using the diff.order config option.
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index e68cc76..70a2893 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -66,7 +66,7 @@ static bool force;
 static bool show_period;
 static bool show_formula;
 static bool show_baseline_only;
-static unsigned int sort_compute;
+static unsigned int sort_compute = 1;
 
 static s64 compute_wdiff_w1;
 static s64 compute_wdiff_w2;
@@ -86,7 +86,7 @@ const char *compute_names[COMPUTE_MAX] = {
 	[COMPUTE_WEIGHTED_DIFF] = "wdiff",
 };
 
-static int compute = COMPUTE_DELTA;
+static int compute = COMPUTE_DELTA_ABS;
 
 static int compute_2_hpp[COMPUTE_MAX] = {
 	[COMPUTE_DELTA]		= PERF_HPP_DIFF__DELTA,
@@ -810,7 +810,7 @@ static const struct option options[] = {
 	OPT_BOOLEAN('b', "baseline-only", &show_baseline_only,
 		    "Show only items with match in baseline"),
 	OPT_CALLBACK('c', "compute", &compute,
-		     "delta,delta-abs,ratio,wdiff:w1,w2 (default delta)",
+		     "delta,delta-abs,ratio,wdiff:w1,w2 (default delta-abs)",
 		     "Entries differential computation selection",
 		     setup_compute),
 	OPT_BOOLEAN('p', "period", &show_period,