Messages in this thread | | | Date | Tue, 12 Aug 2003 20:43:57 +0100 | From | John Bradford <> | Subject | Re: [2.6 patch] add an -Os config option |
| |
> >>+config OPTIMIZE_FOR_SIZE > >>+ bool "Optimize for size" if EMBEDDED > >>+ default n > >>+ help > >>+ Enabling this option will pass "-Os" instead of "-O2" to gcc > >>+ resulting in a smaller kernel. > >>+ > >>+ The resulting kernel might be significantly slower. > > > > > > With most of the gcc's I tried -Os was faster. > > > Why is -Os faster? Fewer cache misses? > > Wouldn't that make -O2 kinda pointless? It seems kinda futile to > optimize for speed just to have it come out slower.
See the comments Linus made earlier this year on the same subject:
http://marc.theaimsgroup.com/?l=linux-kernel&m=104457390406050&w=2
Alan, could Valgrind help us to profile cache hits/misses in different parts of the kernel?
John. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |