Messages in this thread |  | | Date | Mon, 30 Oct 2000 11:27:04 +0100 (CET) | From | Ingo Molnar <> | Subject | Re: 2.2.18Pre Lan Performance Rocks! |
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On Mon, 30 Oct 2000, Jeff V. Merkey wrote:
> For example, if you put a MOV EAX, CR3; MOV CR3, EAX; in a context > switching path, on a PPro 200, you can do about 35,000 context > switches/second
in 2.4 & Xeons we can do more than 100,000 context switches/second, and that is more than enough. But the point is: network IO performance does not depend on context switching speed too much. Also, in Linux we are using global pages which makes kernel-space TLBs persistent even across CR3 flushes.
> [...] There's also the use of segment registers all over the place to > copy from kernel to user and user to kernel space memory. [...]
we do not use the fs segment register for user-space copies anymore, neither in 2.2, nor in 2.4. You must be reading old books and probably forgot to cross-check with the kernel source? :-)
> [...] Having the fast paths you mention does help a lot, but it's the > fact that this goes on at all that will make it tough to walk into a > NetWare shop with Linux and rip out NetWare servers and replace them > unless we look at a NetWare vs. NetLinux (that's what we call it! a > NetWare-like Linux platform).
the worst thing you can do is to mis-identify performance problems and spend braincells on the wrong problem. The problems limiting Linux network scalability have been identified during the last 12 months by a small team, and solved in TUX. TUX is a fileserver, it shouldnt be alot of work to enable it for (TCP-only?) netware serving. It's *done*, Jeff, it's not a hypotetical thing, it's here, it works and it performs.
Ingo
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