Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 6 Sep 2012 11:20:24 +0100
From:      David Chisnall <theraven@FreeBSD.org>
To:        Roman Divacky <rdivacky@FreeBSD.org>
Cc:        Garrett Cooper <yanegomi@gmail.com>, Dimitry Andric <dimitry@andric.com>, freebsd-current@FreeBSD.org, Steve Kargl <sgk@troutmask.apl.washington.edu>
Subject:   Re: Compiler performance tests on FreeBSD 10.0-CURRENT
Message-ID:  <122361C5-7B83-494B-A580-970FAFF83CAA@FreeBSD.org>
In-Reply-To: <20120906084312.GA13223@freebsd.org>
References:  <5046670C.6050500@andric.com> <20120904214344.GA17723@troutmask.apl.washington.edu> <504679CB.90204@andric.com> <20120904221413.GA19395@troutmask.apl.washington.edu> <CAGH67wTQavfh9ExsjypnCjw4yrV2RpdUUjxAD2kaZy-PiDocHA@mail.gmail.com> <50471BEE.6030708@andric.com> <20120905221310.GA97847@troutmask.apl.washington.edu> <20120906084312.GA13223@freebsd.org>

next in thread | previous in thread | raw e-mail | index | archive | help
On 6 Sep 2012, at 09:43, Roman Divacky wrote:

> Was this compiled as amd64 or i386? Also, can you send me the test =
case?
> So that we can explore the difference. The working theory now is SSE =
vs FPU
> mathematics, but it would be nice to see the testcase.

There may also be a difference in whether -ffast-math is the default on =
each compiler.  On x86, this will replace a number of libm calls with =
(much faster, but less accurate) SSE or x87 instructions.  If this is =
enabled by default with clang and not with gcc, it would account for the =
difference. =20

David=



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?122361C5-7B83-494B-A580-970FAFF83CAA>