Martin Turgeon wrote:
Mike Meyer a écrit :
In <[EMAIL PROTECTED]>, Roman Divacky
<[EMAIL PROTECTED]> typed:
you should know what cpu you bought, or just use cpuid (found in ports)
and determine what cpu you have.
Knowing what CPU you bought doesn't help a lot for the case asked
about of "nocona" vs. "prescott". Those are the names of P4 and Xeon
cores, not CPUs - and not the last cores used in either line. cpuid
will tell you what features your CPU supports, but not the name of the
core. So it only helps if you know what you're looking for. P4 and
Xeon are just marketing names, and the features available vary quite a
bit across the lines. Even knowing the core names doesn't help, as
some prescott cored P4s have all the gcc "nocona" features.
Assuming the gcc man page is correct, use cpuid to check the feature
sets of your CPU. If you don't have SSE2, then you should be using
something prior to pentium 4. If you have SSE2 but not SSE3, then you
want pentium-m, pentium4 or pentium4m. If you have SSE3, then you
should be using either nocona or prescott. If you have 64 bit support,
you want nocona, otherwise prescott.
For the record, I believe the nocona cores are:
pentium 4/some prescott, prescott 2m, cedar mill
pentium D/all
core 2 duo/all
All xeons with sse3 except the sossaman cored Xeon LV.
The prescott cores are:
pentium 4/some prescott
xeon lv (sossaman core)
core solo
core duo
<mike
Thanks a lot for the precision, I will use nocona for my dual core Xeon.
Martin
Sorry for not having a reference but it came from an Intel internal
site. Here are the highlights for some of the past players:
Cedar Mill: Last P4 processor. Followup to Prescott.
Conroe: Desktop version of the Core2Duo processor. Mobile equivalent is
Merom.
Dothan: 2nd gen. Pentium M CPU.
Nocona: Xeon server processor code name -- first CPU with EMT64 (amd64)
compatibility [and hence first non-IA64 bit Xeon processor to feature
64-bit compatibility; not sure if it was the first non-IA64 64-bit
designed Intel processor].
Prescott: Single-core processor with HTT. Base CPU for [later
generation] P4 processors, and the dual core Pentium D [basically the
larger cousin of the Northwood CPUs]. Prescott was compacted into Cedar
Mill -- from a 90nm (?) process to 65nm.
Sossaman: Dual-core Xeon processor, based off of Yonah.
Woodcrest: Server version of Conroe/Merom.
Yonah: First Duo/Solo processor. Based off of Dothan.
Some people have claimed that pentium-m is better for Core * based
processors because of the shorter pipelines and lower frequency (found
via a google discussion about gcc and -march, but I can't be sure of its
validity), but pentium-m is a 32-bit CPU, thus it's not an option for
64-bit computing.
Intel suggests using -march=prescott (32-bit) and -march=nocona
(64-bit) with gcc on Core2Duo processors and equivalent Xeons.
You can also find your CPU's type by going to this page:
http://www.intel.com/products/server/processors/index.htm?iid=serv_body+proc,
and searching for the appropriate model number. Your frequency and model
should be reported in your BIOS, if not the first couple lines of dmesg
in FreeBSD.
Cheers,
-Garrett
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