linux-kernel - Re: [PATCH v3 3/5] perf tools: Fix dynamic sort keys to sort properly

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Message-ID: <20160106232645.GC8053@sejong>
Date:	Thu, 7 Jan 2016 08:26:45 +0900
From:	Namhyung Kim <namhyung@...nel.org>
To:	Arnaldo Carvalho de Melo <acme@...nel.org>
CC:	Ingo Molnar <mingo@...nel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Jiri Olsa <jolsa@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	David Ahern <dsahern@...il.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Andi Kleen <andi@...stfloor.org>,
	Wang Nan <wangnan0@...wei.com>
Subject: Re: [PATCH v3 3/5] perf tools: Fix dynamic sort keys to sort properly

On Wed, Jan 06, 2016 at 08:06:43PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Wed, Jan 06, 2016 at 09:54:59AM +0900, Namhyung Kim escreveu:
> > Currently, the dynamic sort keys compares trace data using memcmp().
> > But for output sorting, it should check data size and compare by word.
> > Also it sorted strings in reverse order, fix it.
> 
> Can this be broken down in two patches? This is complex code, lets try
> to make it as bisectable as possible.

OK, I'll break out the string part then.  But I think it doesn't help
much to reduce the complexity.

Thanks,
Namhyung


> 
> - Arnaldo
> 
> > 
> > Before)
> > 
> >   $ perf report -F overhead -s prev_pid,next_pid
> >   ...
> >   # Overhead    prev_pid    next_pid
> >   # ........  ..........  ..........
> >   #
> >        0.39%         490           0
> >        9.12%         225           0
> >        0.04%         224           0
> >        0.51%         731         189
> >        0.08%         731           3
> >        0.12%         731           0
> >        4.82%         729           0
> >        0.08%        1229           0
> >        0.20%         715           0
> >        4.78%         189         225
> >   ...
> > 
> > After)
> > 
> >   $ perf report -F overhead -s prev_pid,next_pid
> >   ...
> >   # Overhead    prev_pid    next_pid
> >   # ........  ..........  ..........
> >   #
> >        0.43%           0           7
> >        0.04%           0          11
> >        0.04%           0          12
> >        0.08%           0          14
> >        0.04%           0          17
> >        0.08%           0          19
> >        0.04%           0          22
> >        0.04%           0          27
> >        0.04%           0          37
> >        0.04%           0          42
> >   ...
> > 
> > Reported-by: Arnaldo Carvalho de Melo <acme@...nel.org>
> > Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> > ---
> >  tools/perf/util/sort.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 46 insertions(+), 1 deletion(-)
> > 
> > diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
> > index 9618a64875c0..264d2b630549 100644
> > --- a/tools/perf/util/sort.c
> > +++ b/tools/perf/util/sort.c
> > @@ -1798,6 +1798,51 @@ static int64_t __sort__hde_cmp(struct perf_hpp_fmt *fmt,
> >  	return memcmp(a->raw_data + offset, b->raw_data + offset, size);
> >  }
> >  
> > +static int64_t __sort__hde_sort(struct perf_hpp_fmt *fmt,
> > +				struct hist_entry *a, struct hist_entry *b)
> > +{
> > +	struct hpp_dynamic_entry *hde;
> > +	struct format_field *field;
> > +	unsigned offset, size;
> > +	int64_t *a64, *b64;
> > +	int32_t *a32, *b32;
> > +	int16_t *a16, *b16;
> > +
> > +	hde = container_of(fmt, struct hpp_dynamic_entry, hpp);
> > +
> > +	field = hde->field;
> > +	if (field->flags & FIELD_IS_DYNAMIC) {
> > +		unsigned long long dyn;
> > +
> > +		pevent_read_number_field(field, a->raw_data, &dyn);
> > +		offset = dyn & 0xffff;
> > +		size = (dyn >> 16) & 0xffff;
> > +	} else {
> > +		offset = field->offset;
> > +		size = field->size;
> > +	}
> > +
> > +	if (field->flags & FIELD_IS_STRING)
> > +		return strcmp(b->raw_data + offset, a->raw_data + offset);
> > +
> > +	switch (size) {
> > +	case 8:
> > +		a64 = a->raw_data + offset;
> > +		b64 = b->raw_data + offset;
> > +		return *b64 - *a64;
> > +	case 4:
> > +		a32 = a->raw_data + offset;
> > +		b32 = b->raw_data + offset;
> > +		return *b32 - *a32;
> > +	case 2:
> > +		a16 = a->raw_data + offset;
> > +		b16 = b->raw_data + offset;
> > +		return *b16 - *a16;
> > +	default:
> > +		return memcmp(b->raw_data + offset, a->raw_data + offset, size);
> > +	}
> > +}
> > +
> >  bool perf_hpp__is_dynamic_entry(struct perf_hpp_fmt *fmt)
> >  {
> >  	return fmt->cmp == __sort__hde_cmp;
> > @@ -1826,7 +1871,7 @@ __alloc_dynamic_entry(struct perf_evsel *evsel, struct format_field *field)
> >  
> >  	hde->hpp.cmp = __sort__hde_cmp;
> >  	hde->hpp.collapse = __sort__hde_cmp;
> > -	hde->hpp.sort = __sort__hde_cmp;
> > +	hde->hpp.sort = __sort__hde_sort;
> >  
> >  	INIT_LIST_HEAD(&hde->hpp.list);
> >  	INIT_LIST_HEAD(&hde->hpp.sort_list);
> > -- 
> > 2.6.4
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