talloc vs malloc speed

[Andreas Schneider]

Hi,

Florian Weimer implemented hwcaps support in glibc. This allows you to drop 
optimized libraries.

The support for this is enabled in openSUSE Tumbleweed right now [1]. I've 
enabled it for libtalloc as you want to to be as fast as possible.


Here are the results from my AMD Ryzen 9 3900X 12-Core processor.

talloc x86_64_v1 (testsuite compiled with -O0)

test: speed
# TALLOC VS MALLOC SPEED
talloc:       46623469 ops/sec
talloc_pool:  74121933 ops/sec
malloc:       66443400 ops/sec
success: speed

=> talloc is 30% slower



talloc x86_64_v3 (testsuite compiled with -O0)

test: speed
# TALLOC VS MALLOC SPEED
talloc:       47783809 ops/sec
talloc_pool:  75068595 ops/sec
malloc:       68073710 ops/sec
success: speed

=> talloc is 30% slower



talloc x86_64_v3 (testsuite compiled with -O2)
test: speed
# TALLOC VS MALLOC SPEED
talloc:       50633005 ops/sec
talloc_pool:  74245533 ops/sec
malloc:      219259200 ops/sec
success: speed

=> talloc is 77% slower


It looks like the optimizer is able to optimize the code a lot more if malloc 
is used.

I wonder if it would be possible to give the optimizer more hints. Maybe 
Florian has some ideas :-)


Best regards


	Andreas


P.S. The talloc website states it is 4% slower than malloc. This was probably 
a long long time ago ;-)


[1] https://www.phoronix.com/news/glibc-hwcaps-RFC
[2] https://news.opensuse.org/2023/03/02/tw-gains-optional-optimizations/

-- 
Andreas Schneider                      asn at samba.org
Samba Team                             www.samba.org
GPG-ID:     8DFF53E18F2ABC8D8F3C92237EE0FC4DCC014E3D