Messages in this thread | | | From | David Laight <> | Subject | RE: FYI -ffreestanding shrinks kernel by 2% on x86_64 | Date | Mon, 13 May 2019 09:13:25 +0000 |
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From: Ingo Molnar > Sent: 12 May 2019 10:32 ... > Has anyone investigated by any chance where the -ffreestanding space > savings come from mostly - is it mostly in cold paths, or does it make or > hot codepaths more efficient as well? > > If it's the latter then the kernel would be directly faster as well > (fewer instructions executed), not just indirectly from better cache > packing, I suppse?
My guess is that -ffreestanding stops gcc inlining memcpy() (etc). The calls can be smaller than the inline code, but will (probably) run more slowly.
David
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