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FreeBSD on the Athlon64 in 64bit vs Pentium4 3.2E

Posted by Hemos on from the compare-and-contrast dept.

veliath writes "Came by a comparison from about three weeks ago, between two systems running FreeBSD. One is an Athlon64 running FreeBSD in 64bit mode and the other a Pentium4 3.2E running FreeBSD in 32bit mode."

3 of 74 comments (clear)

  1. Re:HT & threads by Anonymous Coward · · Score: 5, Interesting

    While I don't know about FreeBSD's threads sucking as far as I could tell none of the tests would've stressed the threading system.

    The tests didn't really work to hyper-threading's advantages. Take the builds with multiple jobs running at the same time. That's more about running separate applications as separate processes and that's not what hyper-threading's advantage is because they arn't separate thread at all.

    HT is more for true multithreaded applications like Photoshop or something and none of the benchmarks were anything like that.

  2. What about multiple processors? by RT+Alec · · Score: 5, Interesting

    Nice comparision, but what about dual or quad processor systems? I have recently installed both FreeBSD 4.9 and 5.2.1 on (almost) identical dual-Xeon servers. Both are operating as if they had 4 processors (due to HTT). How would the Athelon, etc. stack up with this setup (seriously, I'd like to know)? Maybe HTT realy shines on multiple CPU systems, not just mon-processor? Maybe.

    BTW- FreeBSD (either version) on a brand new Dell rack-mount server, with hardware RAID, 2GB RAM, dual processor (of course) makes for a very fast server! I have them configured mostly as web servers, a number of Perl generated dynamic pages (ad serving mostly), rsync, CVS repository, Cyrus and Sendmail (w/SASL AUTH and TLS/SSL), MySQL, and a custom rsync staging/production environment. When I run top, it sure is nice to every now and then see 2 processors at almost 100% utilization, yet also show 50% idle. I have no benchmarks to report, alas these are production machines in use.

  3. Re:HT & threads by aminorex · · Score: 5, Interesting
    HT does wonders for the P4 in the bandwidth tests, because they are not taxing the execution core; they are only stressing the limits of those parts of the CPU which are replicated. In fact, I can go a step further and say that they aren't even taxing those parts in any meaningful way, because the P4 just plain has fat pipes. Forthcoming dual-channel revisions of the Athlon64 will do another leap-frog, and put that architecture's bandwidth in the lead for a while, but it hasn't happened yet.

    The real-world apps demonstrate that the 5% of die space spent on HT doesn't result in much more leveraging of the execution core, in practice. I can't imagine why anyone would care what the P4 numbers were without HT, since no one will ever run it that way now that OSen are supporting it.

    As regards FreeBSD's kernel threads, the answer is "not really" since the overwhelming bulk of the benchmarks was spent in userspace (less so for the compile benchmarks than for the crypto ones). Notice that the user time numbers favored the Athlon64 no less than did the wall time numbers.

    I think it's interesting that the synthetic benchmarks all favored the P4 (a highly academic design) while the user load tests all favored the 64.

    --
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