Re: [PATCH] x86: Align jump targets to 1 byte boundaries

From: H. Peter Anvin
Date: Fri Apr 10 2015 - 09:19:32 EST


On 04/10/2015 05:50 AM, Denys Vlasenko wrote:
>
> However, I'm an -Os guy. Expect -O2 people to disagree :)
>

The problem with -Os is that the compiler will make *any* tradeoffs to
save a byte. It is really designed to squeeze as much code into a
fixed-size chunk, e.g. a ROM, as possible.

We have asked for an -Okernel mode from the gcc folks forever. It
basically would mean "-Os except when really dumb."

As far as the 16-byte alignment, my understanding is not that it is
related to the I$ but rather is the decoder datum.

-hpa


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/