CPUTYPE in general - was Re: Which CPUTYPE for a dualcore Xeon
on AMD64
Garrett Cooper
youshi10 at u.washington.edu
Tue Jun 26 03:34:51 UTC 2007
Martin Turgeon wrote:
> Mike Meyer a écrit :
>> In <20070625192308.GA14544 at freebsd.org>, Roman Divacky
>> <rdivacky at freebsd.org> 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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