Date: Wed, 18 Feb 2009 17:53:56 -0500 From: Jung-uk Kim <jkim@FreeBSD.org> To: freebsd-questions@freebsd.org Cc: Kailash Kailash <kailash.kailash@zscaler.com> Subject: Re: FreeBSD 7.O compiled code is very slow Message-ID: <200902181753.59988.jkim@FreeBSD.org> In-Reply-To: <499c7357.14098e0a.1394.ffffda2d@mx.google.com> References: <499c7357.14098e0a.1394.ffffda2d@mx.google.com>
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On Wednesday 18 February 2009 03:44 pm, Kailash Kailash wrote: > I am using FreeBSD 7.0 in 64 BIT mode. Same code compiled on BSD > 7.0 runs 50% speed (as expected by CPU and code architecture) > compared to BSD 6.2. Here is one real code with binary output. On > 3.0 GHz Woodcrest processor, I am able to copy from one cache to > another cache at the speed of 24Gbytes/second verses 12 > Gbytes/second. Any help is appreciated. You may try "-fno-ivopts". I think the bug is: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27440 Jung-uk Kim > Thanks, > > Kailash > > > > Source-code: > > #define BACKWARD_MEMCOPY_WITH_TYPE(dp, sp, len, type) > BACKWARD_MEMCOPY((type*)(dp), (const type*)(sp), > ((len)+(sizeof(type)-1))/sizeof(type)) > > > > #define BACKWARD_MEMCOPY(dp, sp, len) \ > > do { \ > > smwbits __len = len; /* must be signed value */ > \ > > while (--__len >= 0) \ > > (dp)[__len] = (sp)[__len]; \ > > } while (0) > > > > BSD 6.2 code > > 0x00000000004353b2 <smcli_memory_copy_performance+434>: mov > 0x8(%rbp,%rdx,8),%rax > > 0x00000000004353b7 <smcli_memory_copy_performance+439>: mov > %rax,0x48(%r12,%rdx,8) > > 0x00000000004353bc <smcli_memory_copy_performance+444>: dec %rdx > > 0x00000000004353bf <smcli_memory_copy_performance+447>: jns > 0x4353b2 <smcli_memory_copy_performance+434> > > > > BSD 7.0 code > > 0x000000000040cb80 <smcli_memory_copy_performance+272>: mov > 0xfffffffffffffff8(%rsi),%rax > > 0x000000000040cb84 <smcli_memory_copy_performance+276>: mov > %rax,0xfffffffffffffff8(%rcx) > > 0x000000000040cb88 <smcli_memory_copy_performance+280>: sub > $0x8,%rsi > > 0x000000000040cb8c <smcli_memory_copy_performance+284>: sub > $0x8,%rcx > > 0x000000000040cb90 <smcli_memory_copy_performance+288>: sub > $0x1,%rdx > > 0x000000000040cb94 <smcli_memory_copy_performance+292>: jns > 0x40cb80 <smcli_memory_copy_performance2+272>
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