Messages in this thread | | | Subject | fresh data was Re: [PATCH] X86-32: Let gcc decide whether to inline memcpy was Re: New x86 warning | From | Andi Kleen <> | Date | Thu, 23 Apr 2009 08:08:38 +0200 |
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Andi Kleen <andi@firstfloor.org> writes:
>> > Quick test here: >> >> How about you just compile the kernel with gcc-3.2 and compare the number >> of calls to memcpy before-and-after instead? That's the real test. > > I waited over 10 minutes for the full vmlinux objdumps to finish. sorry lost > patience. If someone has a fast disassembler we can try it. I'll leave > them running over night, maybe there are exact numbers tomorrow. > > But from a quick check (find -name '*.o' | xargs nm | grep memcpy) there are > very little files which call it with the patch, so there's some > evidence that there isn't a dramatic increase.
I let the objdumps finish over night. On my setup (defconfig + some additions) there are actually less calls to out of line memcpy/__memcpy with the patch. I see only one for my defconfig, while there are ~10 without the patch. So it makes very little difference. The code size savings must come from more efficient code generation for the inline case. I haven't investigated that in detail though.
So the patch seems like a overall win.
-Andi
-- ak@linux.intel.com -- Speaking for myself only.
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