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gstvalue: Speed up gst_value_intersect/_subtract

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Both gst_value_intersect and gst_value_subtract will call
gst_value_compare if one of their arguments isn't a list.

gst_value_compare will then re-do a check to see if one of
the arguments is a list (for the special case of comparing a unitary
value with a list of length 1).

The problem is that the various G_VALUE_HOLDS represent an expensive
amount of calling gst_value_compare (almost half of it) to see if
the provided arguments are list. These checks can be done without
when we know that the arguments aren't lists.

* Create a new "nolist" gst_value_compare which avoids that special
  case comparision

Benchmarks:
 valgrind/callgrind: average speedup in instruction calls for
 gst_value_intersect and gst_value_subtract is around 56% (Makes 63%
 of the calls it used to take previously)

 tests/benchmarks/capsnego: With default settings (depth 4, children 3
 607 elements), time taken for transition from READY to PAUSED:
   Before : 00.391519153
   After  : 00.220397492
    56% of the time previously used, +77% speedup

https://bugzilla.gnome.org/show_bug.cgi?id=731756
This commit is contained in:
Edward Hervey 2014-06-17 07:31:48 +02:00 committed by Edward Hervey
parent 5c62bce85c
commit b0b20b44e5
1 changed files with 25 additions and 14 deletions
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39
gst/gstvalue.c
View file

@ -4460,6 +4460,27 @@ gst_value_list_equals_range (const GValue * list, const GValue * value)
return FALSE;
}
/* "Pure" variant of gst_value_compare which is guaranteed to
* not have list arguments and therefore does basic comparisions
*/
static inline gint
_gst_value_compare_nolist (const GValue * value1, const GValue * value2)
{
GstValueCompareFunc compare;
if (G_VALUE_TYPE (value1) != G_VALUE_TYPE (value2))
return GST_VALUE_UNORDERED;
compare = gst_value_get_compare_func (value1);
if (compare) {
return compare (value1, value2);
}
g_critical ("unable to compare values of type %s\n",
g_type_name (G_VALUE_TYPE (value1)));
return GST_VALUE_UNORDERED;
}
/**
* gst_value_compare:
* @value1: a value to compare
@ -4476,7 +4497,6 @@ gst_value_list_equals_range (const GValue * list, const GValue * value)
gint
gst_value_compare (const GValue * value1, const GValue * value2)
{
GstValueCompareFunc compare;
GType ltype;
g_return_val_if_fail (G_IS_VALUE (value1), GST_VALUE_LESS_THAN);
@ -4533,17 +4553,8 @@ gst_value_compare (const GValue * value1, const GValue * value2)
return GST_VALUE_EQUAL;
}
if (G_VALUE_TYPE (value1) != G_VALUE_TYPE (value2))
return GST_VALUE_UNORDERED;
compare = gst_value_get_compare_func (value1);
if (compare) {
return compare (value1, value2);
}
g_critical ("unable to compare values of type %s\n",
g_type_name (G_VALUE_TYPE (value1)));
return GST_VALUE_UNORDERED;
/* And now handle the generic case */
return _gst_value_compare_nolist (value1, value2);
}
/*
@ -4760,7 +4771,7 @@ gst_value_intersect (GValue * dest, const GValue * value1,
if (G_VALUE_HOLDS (value2, ltype))
return gst_value_intersect_list (dest, value2, value1);
if (gst_value_compare (value1, value2) == GST_VALUE_EQUAL) {
if (_gst_value_compare_nolist (value1, value2) == GST_VALUE_EQUAL) {
if (dest)
gst_value_init_and_copy (dest, value1);
return TRUE;
@ -4857,7 +4868,7 @@ gst_value_subtract (GValue * dest, const GValue * minuend,
}
}
if (gst_value_compare (minuend, subtrahend) != GST_VALUE_EQUAL) {
if (_gst_value_compare_nolist (minuend, subtrahend) != GST_VALUE_EQUAL) {
if (dest)
gst_value_init_and_copy (dest, minuend);
return TRUE;