Re: gcc 3.2 not faster

[GOTO Masanori <gotom@debian.or.jp>]

At Wed, 8 Jan 2003 15:38:04 +0100,
Russell Coker wrote:
> I thought that gcc 3.2 was supposed to be faster, however I have just done 
> some benchmarks to show the opposite:
> 
> GCC 2.95:
> 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.

IIRC, I saw such similar performance problem between gcc-2.7.2 and
egcs 1.1 in 1999 on Linux and FreeBSD.  gcc-2.7.2 is faster than egcs,
with read/write operation, the program compiled by egcs cannot show
raw disk seaquential throughput.  Disk lamp is switched so frequently,
thus something blocked its IO.  I was surprised.

However, I don't know its cause, so I don't know it's same problem or
not...  I would like to know what is the problem.

Regards,
-- gotom