On 08/09/2012 04:16 PM, H. Peter Anvin wrote:
> On 08/09/2012 03:25 PM, Steven Rostedt wrote:
>>>
>>> It might be better to improve gcc to move really cold branches out of
>>> line (really, really far away), and use the compiler to do this, rather
>>> than to use an extra indirection that adds bloat and complexity to the
>>> kernel.

Oh, you mean like: -freorder-blocks-and-partition

>>
>> I think modifying gcc is something that can help more than tracing. But
>> that's been a pipe dream for such a long time that I've started dreaming
>> about winning a gold medal in the Olympics instead. Standing on the
>> podium listening to the crowd chanting your name along with your country
>> is more fun to dream about than seeing your unlikely code stop becoming
>> hurdles for the CPU sprinters.
>>
>
> At one point, maybe, but lately we have had a lot more traction from the
> gcc developers, giving us features like __fentry__ and asm goto.
>

I don't claim that -freorder-blocks-and-partition is bug free, but I 
imagine that the GCC developers would be open to fixing any bugs found.

David Daney