Re: [PATCH] tracing: Cleanup the convoluted softirq tracepoints

[H. Peter Anvin]

On 10/19/2010 06:52 PM, Jason Baron wrote:
> 
> thanks Steve. I was about to say this. When CONFIG_CC_OPTIMIZE_FOR_SIZE
> is not set we don't get the double 'jmp' and the tracepoint code is
> moved out of line. It was mentioned that a number of distros ship with
> CONFIG_CC_OPTIMIZE_FOR_SIZE not set, and as Steve mentioned my original
> patch set was conditional on !CONFIG_CC_OPTIMIZE_FOR_SIZE.
> 
> using hot/cold labels gcc can fix the CONFIG_CC_OPTIMIZE_FOR_SIZE case,
> but its a non-trivial amount of work for gcc. I was hoping that if jump
> labels are included, we could make the gcc work happen.
> 

That's fair.  I think jump labels are still a win even in the
double-jump case (especially if the the tracepoint turns into a NOP
rather than a JMP.)

Code generated with -Os has a bunch of other problems, too.

	-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/