Messages in this thread |  | | From | Keith Owens <> | Subject | Re: cpu-2.5.64-1 | Date | Sun, 16 Mar 2003 22:53:19 +1100 |
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On Sun, 16 Mar 2003 03:32:54 -0800, William Lee Irwin III <wli@holomorphy.com> wrote: >On Sun, Mar 16, 2003 at 10:12:24PM +1100, Keith Owens wrote: >> Some of the 64 bit archs implement test_bit() as taking int * instead >> of long *. That generates unoptimized code for the case of NR_CPUS < >> 64.
Come to think of it, using any of the bitops generates unoptimized code for cpu mask testing when we know that NR_CPUS will fit into a single long. For NR_CPUS <= 8*sizeof(long), using mask & (1UL << cpu) removes the unnecessary array calculations.
>What's the state of 2.5.x on the big machines where you're at?
I could tell you, but then marketing would kill me :( Wait a bit.
>Another thought I had was wrapping things in structures for both small >and large, even UP systems so proper typechecking is enforced at all >times. That would probably need a great deal of arch sweeping to do, >especially as a number of arches are UP-only (non-SMP case's motive #2).
Keep the optimized model, where cpu_online_map is #defined to 1 for UP. Changing it to an ADT just to get type checking on architectures that only support UP looks like a bad tradeoff.
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