[mythtv-users] 32 vs. 64 bit, any significant difference?
belcampo
belcampo at zonnet.nl
Thu Dec 17 22:21:54 UTC 2009
Robin Hill wrote:
> On Thu Dec 17, 2009 at 08:31:59PM +0100, belcampo wrote:
>
>> Johnny wrote:
>>> Another benefit is that the compiler can make much more efficient
>>> optimizations because x86-64 includes all the modern changes to the
>>> x86 ISA (SSE etc) that modern chips support. When you use 32-bit it is
>>> compiled against the ISA that an Intel 386 used or maybe a 686 (e.g.
>>> Pentium II, Pentium III). But I think in everyday use you aren't
>>> likely to feel much difference from this (approximately 5%
>>> improvement). But in processes that are very computationally intense
>>> and benefit from newer ISA changes like SSE, then you will see larger
>>> improvements on the order of 10%-20%. Much of the MMX and SSE
>>> extensions added op-codes for vector operations, etc, that are
>>> targeting at multimedia stuff like transcoding. So that is one of the
>>> areas that sees the most benefit.
>> Are there any hard facts that prove these assumptions ?
>> Transcoding 32 vs 64bit 512MB vs 2-8GB
>>
> There's some transcoding figures at:
> http://hans.fugal.net/blog/2008/04/20/64-bit-transcoding/
>
> Not transcoding, but there's some comparisons of other operations at:
> http://tuxradar.com/content/ubuntu-904-32-bit-vs-64-bit-benchmarks
>
> AMD have some a good general comparison at:
> http://forums.amd.com/devblog/blogpost.cfm?threadid=93648&catid=317
Thanks for the links. 5-10% and
First there is the larger memory footprint. Binaries get larger because
of an increased pointer size and 64-bit operands. This leads to higher
memory transfer load and therefore increases cache utilization.
From my observations over the last >20 years, only an increase of >30%
is noticed by an avarage user. A faster/less-loaded disk often helps
more in responsivnes, hence my < 350MB total installation-size and
memory use as
free -m
total used free shared buffers cached
Mem: 487 478 8 0 0 301
-/+ buffers/cache: 177 309
Swap: 0 0 0
used for:
4924 mythtv 15 0 214m 70m 22m S 0 14.5 0:11.87
firefox-bin
4018 root 15 0 241m 31m 8512 S 0 6.4 0:19.23
mythbackend
3766 root 15 0 61360 22m 6420 S 1 4.7 0:17.62 X
3784 mysql 16 0 113m 19m 4816 S 0 4.0 0:06.86 mysqld
3777 root 15 0 15224 5944 3476 S 0 1.2 0:00.02 httpd
3885 mythtv 16 0 10956 5440 3600 S 0 1.1 0:00.36 wmaker
>
> Cheers,
> Robin
>
>
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