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Graham Banks
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 Posted: Wed Jul 30, 2003 1:32 pm Post subject: Multiple inheritance performance hit |
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Does using multiple inheritance introduce any more performance overhead than
single inheritance?
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tom_usenet
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| Posted: Wed Jul 30, 2003 4:30 pm Post subject: Re: Multiple inheritance performance hit |
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On Wed, 30 Jul 2003 14:32:45 +0100, "Graham Banks"
<grahambanksRemoveIfYouAreNotASpamBot (AT) sol-digi (DOT) com> wrote:
| Quote: | Does using multiple inheritance introduce any more performance overhead than
single inheritance?
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It depends on the implementation, but calling a virtual function where
virtual multiple inheritence is involved will typically be slightly
slower than a normal virtual function. The vtable for a class involved
in multiple inheritence will probably be larger too.
Tom
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Alex Vinokur
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| Posted: Mon Aug 04, 2003 5:14 pm Post subject: Re: Multiple inheritance performance hit |
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"Graham Banks" <grahambanksRemoveIfYouAreNotASpamBot (AT) sol-digi (DOT) com> wrote
| Quote: | Does using multiple inheritance introduce any more performance overhead than
single inheritance?
|
Multiple inheritance vs. single inheritance
===========================================
C/C++ Performance Tests
=======================
Using C/C++ Program Perfometer
http://sourceforge.net/projects/cpp-perfometer
http://alexvn.freeservers.com/s1/perfometer.html
Environment
-----------
Windows 2000 Professional
CYGWIN_NT-5.0 1.3.22(0.78/3/2)
Intel(R) Celeron(R) CPU 1.70 GHz
GNU gcc/g++ version 3.2 20020927 (prerelease)
Compilation : No optimization
===================== Classes : BEGIN =====================
====================
Hierarchy of classes
====================
Foo0
| Quote: |
Foo1
_____________|_____________
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__________|__________ |
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Foo2_v1 Foo2_v2 Foo2
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___________________| |
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Foo3_m Foo3
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Foo4_m Foo4 |
=====================
Definition of classes
=====================
// --------------
class Foo0
{
public:
Foo0 () {}
};
// --------------
class Foo1 : public Foo0
{
public:
Foo1 () : Foo0 () {}
};
// --------------
class Foo2_v1 : virtual public Foo1
{
public:
Foo2_v1 () : Foo1 () {}
};
// --------------
class Foo2_v2 : virtual public Foo1
{
public:
Foo2_v2 () : Foo1 () {}
};
// --------------
class Foo2 : public Foo1
{
public:
Foo2 () : Foo1 () {}
};
// --------------
class Foo3_m : public Foo2_v1, public Foo2_v2
{
public:
Foo3_m () : Foo1 (), Foo2_v1 (), Foo2_v2 () {}
};
// --------------
class Foo3 : public Foo2
{
public:
Foo3 () : Foo2 () {}
};
// --------------
class Foo4_m : public Foo3_m
{
public:
Foo4_m () : Foo1 (), Foo3_m () {}
};
// --------------
class Foo4 : public Foo3
{
public:
Foo4 () : Foo3 () {}
};
===================== Classes : END =======================
================ Performance tests : BEGIN ================
==================
Creating instances
==================
Summary test results
====================
#----------------------------------------------------------
# Comparison : multiple inheritance vs. single inheritance
#----------------------------------------------------------
# Resource Name : user time used (via rusage)
# Resource Cost Unit : milliseconds (unsigned long long)
# Resource State Unit : timeval
#----------------------------------------------------------
: ---------------------------------------------
: Foo0 : Level-0 base class -> 9
:
: Foo1 : Level-1 single inheritance -> 13
:
: Foo2 : Level-2 single inheritance -> 20
: Foo2_v1 : Level-2 virtual inheritance -> 20
: Foo2_v2 : Level-2 virtual inheritance -> 20
:
: Foo3 : Level-3 single inheritance -> 25
: Foo3_m : Level-3 multiple inheritance -> 42
:
: Foo4 : Level-4 single inheritance -> 32
: Foo4_m : Level-4 multiple inheritance -> 45
: ---------------------------------------------
Raw Log : http://groups.google.com/groups?selm=bglcid%24q2qeg%241%40ID-79865.news.uni-berlin.de
================ Performance tests : END ==================
Regards,
=====================================
Alex Vinokur
mailto:alexvn (AT) connect (DOT) to
http://mathforum.org/library/view/10978.html
=====================================
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