Messages in this thread | | | Date | Mon, 13 Feb 2006 12:34:03 -0800 | From | Stephane Eranian <> | Subject | Re: perfmon2 code review: 32-bit ABI on 64-bit OS |
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Bryan,
On Fri, Feb 10, 2006 at 10:27:02AM -0800, Bryan O'Sullivan wrote: > > On some 64-bit arches (e.g. x86_64), most userspace code is 64-bit, > while on others (e.g. powerpc), most is 32-bit. Reducing the number of > things that a userspace tool or library writer can trip over seems like > a good thing here, even if it slightly complicates perfmon's internals. > > > Note that there are similar issues with the remapped sampling buffer. > > There, you need to explicitly compile your tool with a special option > > to force certain types to be 64-bit (size_t, void *). > > It's pretty normal to just use 64-bit quantities in these cases, and > cast appropriately. >
So if I understand you correctly, you are saying it is best to have bitmasks hardcoded to u64 and have the kernel cast to match the bitmap_*() interface. This would not cause any alignment problems on neither 32-bit nor 64-bit system.
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