Re: gcc 3.2 not faster
On Wed, 8 Jan 2003 17:49, Daniel Jacobowitz wrote:
Version 1.93b write read putcNT getcNT putc getc putcU getcU
lyta 437 559 9052 9478 1694 1734 24757 48029
GCC 3.2:
Version 1.93b write read putcNT getcNT putc getc putcU getcU
441 568 7955 8573 1617 1698 18731 28544
> > putcU/getcU is putc_unlocked() and getc_unlocked().
> >
> > putcNT/getcNT is putc() and getc() in a program that's linked without
> > thread support.
> >
> > When linked with thread support putc/getc do extra locking which gives
> > about the same speed on both compilers.
> >
> > The source to this is in http://www.coker.com.au/bonnie++/experimental/
>
> High numbers good? Low numbers good? Looks like high numbers from the
> above. Would you care to analyze the difference so that something can
> be done about it, or to try it with gcc-snapshot?
It's fairly simple. The benchmark creates a 40MB file and then reads and
writes it a byte at a time.
The tests are done by two programs, one is linked with -lpthread and does
everything except the NT (Not Threaded) tests.
The first thing to note is that getc_unlocked() and putc_unlocked() give 76%
and 59% the performance that they got when compiled with GCC 2.95. All tests
are done with the same libc6, so it's just a matter of GCC optimising shared
object calls.
As for trying it with gcc-snapshot, currently the latest experimental version
of Bonnie++ does not compile on GCC 3.2 which is something I have to work on.
The getc_putc test compiles OK and I had a hunch it would be worth running to
compare the GCC versions...
--
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