On Sat, Mar 06, 2010 at 11:42:51AM +0100, Jerome Vizcaino wrote: > Package: libc6 > Version: 2.10.2-6 > Severity: normal > > Hi, > > After many tests and research I've come to the conclusion that the float > variants > of > sin/cos (and maybe others) are anormaly slow Debian amd64. > The performance loss is really impressive (around 8 to 9 times slower). > I've attached the prog used to make my experiments and used it in the > following > cases. > > + Lenny-amd64: sinf/cosf is really slow > + Lenny-i386: float performance is ok (faster than the cos/sin using double) > + Sid-amd64: sinf/cosf slow > + Lenny-amd64 using lenny-i386 binary and 32bits libs: float performance is > OK.
On amd64, only sincos has an optimized version, sincosf is using the generic C implementation. On i386, there are optimized version of both sincos and sincosf > + OpenSuse 64 bits (10.3 and 11.1): using the binary compiled on lenny-amd64, > the tests run fine ! > => The problem is not compiler related. > > There seems to be a problem with the way libm is compiled for the amd64 > architecture on Debian. > This is why the OpenSuse test was run: the problem is somewhere in the > compile > chain or debian specific patches. > The problem is clearly not Debian specific, and is also present upstream. OpenSuse is probably using a patch to workaround the problem. -- Aurelien Jarno GPG: 1024D/F1BCDB73 aurel...@aurel32.net http://www.aurel32.net -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
