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On Thu, 2004-03-18 at 09:35, Nick Van Vlaenderen wrote: |
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> I am going to install Gentoo Linux on a server with a Pentium IV CPU |
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> with Hyper-Threading. My question is, does anyone has experience with |
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> that kind of servers? I know that I need to enable SMP in the kernel, |
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> but do I need to use something specific to make Gentoo use the 2 |
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> virtual CPU's and not only one? And how can I have better performance |
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> .. and so on? |
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Yes, enable SMP. If HT is really enabled for your box (in the BIOS), it |
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should just work. If you happen to use an 2.6 series kernel, you have |
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the option of specifying the maximum number of processors to support; |
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set this to twice the number of real processors, i.e. the total of real |
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and virtual processors. |
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In my experience with a dual 2.4 GHz P4-Xeon system, the optimal make |
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parallelism setting is -j4. I found that I could compile the 2.6 kernel |
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in about 3:40 clock time, although I was not (according to time) using |
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100% CPU (slightly less than 10 min CPU time). Usually my rule of thumb |
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is twice the number of processors, so I tried -j8 (did I mention 1 GB of |
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RAM?). This reduced the compile time very slightly (about 3:20), and |
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essentially maxed out the CPU time (over 12 min). But clock time is the |
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thing that really matters, and the improvement was so small I decided to |
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stick with -j4. |
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This is a *very* simple benchmark, and doesn't account for things like |
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caching and such, so don't draw too many conclusions. |
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-- |
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Andy Dustman <adustman@×××××××××.edu> |
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Office of Information Technology, Terry College of Business, UGA |