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Re: [SLUG] Re: pentium M series


O Plameras wrote:

Visser, Martin wrote:

All,

I just "googled" for "benchmark performance linux kernel i386 versus
i686" and found nothing of any import. I am just wondering if anyone has
bothered doing this. It would be nice to know what the tradeoff is
between performance and convenience of not needing to know the CPU
architecture. Using multi-CD distros I would also choose the closest
matching kernel, but for my Ubuntu installs I haven't bothered.

Martin


Hi Martin,

This post that follows claims there's no demonstrated evidence to show
significant real performance advantage:
https://www.redhat.com/archives/fedora-devel-list/2005-January/msg00759.html

Architecture wise, some changes from i386 to i586:
1. Native floating point in i586 (present in i486 but disabled, option to install co-processor in i386) 2. Superscalar arch in i586 that allows pipelining (so allows more than one instruction per clock cycle) 3. 64-bit data path instead of 32-bit (so this doubles amount of data fetch from memory per clock cycle) This does not mean i586 can execute 64-bit applications; registers are still 32-bit.
4. MMX instructions for multimedia.


I missed to include these comments.

I just want to add these implications to Linux users like ourselves as far as the above are concerned. 1. If you have x86 - i686, it is clearly advantageous to install kernel and applications compiled or optimised for i686. 2. If you have x86 - i386, then install i386 kernel because clearly, i686 kernel will crash when
installed.

Suppliers of Linux distributions provides CD that install i386 as default for obvious reason, like
they want to maximise platform compatibility.

O Plameras