On Saturday 15 December 2007 04:57:47 pm Nathaniel Price wrote: > I've recently upgraded my server to an AMD Athlon 64 X2 4000+. As a > pleasant surprise, the existing installation of Ubuntu 6.06 LTS > (which was originally installed for an Athlon XP 2600+ and uses a > 32bit i386 kernel) worked just fine after the upgrade, with no > tinkering needed aside from reconfiguring X to use the onboard video. > Score 1 for Linux. :)
I'll answer to a whole bunch of comments in this email. First, Linux (the kernel) is very smart. It is capable of creating a kernel that best uses the features of a particular processor/memory configuration. Distro's try to balance things out by creating non-smp and smp kernels. Why? Because there is a performance boost in the process scheduler if it doesn't have to deal with multiple processors. Additionally, the latest kernels (since about 2.6.21 or so) have scheduler improvements for hyperthreaded processors and multicore processors. Whether Ubuntu enables such enhancements or not is out of my realm of knowledge, as are countless many things. My guess is that they would be enabled. Second, the issue of using 686 or k7 kernels.if you have a new Athlon 64 X16 50,000+++, I wouldn't use a k7 kernel on it because the optimizations for "Athlon" apply for the old Athlon XP chips, not the new 64-bit, dual core chips. For a list of chips supported by GCC, see http://gcc.gnu.org/onlinedocs/gcc-4.2.2/gcc/i386-and-x86_002d64-Options.html. Third, optimizing for a specific processor (Pentium 4, Opteron, etc.) For what I've read, there is very little difference in performance when telling the compiler to optimize for 686 (Pentium II and above) and your new-super-cool processor. Additionally, to get the best performance out of it, you would have to build all code with those optimizations, not just the kernel. Gentoo does this, but I'm sure Ubuntu doesn't. I think all packages are compiled for "686" systems. Forth, my desktop has 2 Core duo chips for 4 processor cores total. Linux sees them just fine. Doing virtualization on them is really nice. But remember, having 4 cores at 2 GHz is not the same as having 8 GHz. Applications need to be multi-threaded in order to make use of the extra cores. gzip/bzip2 are classic examples. Since they are single-thread applications, compressing a file will only use one core. However, if you have 4 cores, you can compress 4 files at the same time with little decrease in performance. -- Alberto Treviño [EMAIL PROTECTED] Testing Center Brigham Young University -------------------- BYU Unix Users Group http://uug.byu.edu/ The opinions expressed in this message are the responsibility of their author. They are not endorsed by BYU, the BYU CS Department or BYU-UUG. ___________________________________________________________________ List Info: http://uug.byu.edu/mailman/listinfo/uug-list
