Messages in this thread | | | Subject | Re: [2.6 patch] add a config option for -Os compilation | From | Andi Kleen <> | Date | 18 Oct 2003 21:19:32 +0200 |
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Andrew Morton <akpm@osdl.org> writes:
> And bear in mind that you can see significant changes in benchmark results > between equivalent kernels even when the optimisation level is kept the > same, due to aliasing and alignment luck.
It also depends on a lot on the compiler version. On 2.95 it was common wisdom that -Os is often fastest, but that changed in later versions.
Best would be actually a mix of both - setting it case by case. That's already done in specific cases, e.g. ACPI is always compiled with -Os. This could be done for other files which are clearly slow path too.
Profile feedback is unfortunately not an option because it is too unpredictable and causes maintenance problems.
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