Messages in this thread Patch in this message | | | Date | Thu, 23 Feb 2006 09:08:59 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: Patch to reorder functions in the vmlinux to a defined order |
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On Thu, 23 Feb 2006, Arjan van de Ven wrote: > > > > I think you would first need to move the code first for that. Currently it starts > > at 1MB, which means 1MB is already wasted of the aligned 2MB TLB entry. > > > > I wouldn't have a problem with moving the 64bit kernel to 2MB though. > > that was easy since it's a Config entry already ;)
Btw, the "low TLB entry" for the direct-mapped case can't be used as a hugetlb page anyway, due to the MMU splitting it up due to the special MTRR regions, if I recall correctly.
So this is probably a bigger performance win than just the difference between using one or two TLB entries.
The same should be true on x86, btw. Where we should use a physical start address of 4MB for best performance.
Does anybody want to run benchmarks? (Totally untested, may not boot, might physically accost your pets for all I know).
Linus
--- diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig index 0afec85..d2b1df8 100644 --- a/arch/i386/Kconfig +++ b/arch/i386/Kconfig @@ -715,7 +715,7 @@ config PHYSICAL_START hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP) default "0x1000000" if CRASH_DUMP - default "0x100000" + default "0x400000" help This gives the physical address where the kernel is loaded. Normally for regular kernels this value is 0x100000 (1MB). But in the case - 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/
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