Re: [PATCH 4/4] virtio_ring: unify direct/indirect code paths.

Rusty Russell
2014-05-29T11:09:10Z

Peter Zijlstra <peterz@infradead.org> writes:
> On Thu, May 29, 2014 at 04:56:45PM +0930, Rusty Russell wrote:
>> Before:
>> gcc 4.8.2: virtio_blk: stack used = 392
>> gcc 4.6.4: virtio_blk: stack used = 480
>>
>> After:
>> gcc 4.8.2: virtio_blk: stack used = 408
>> gcc 4.6.4: virtio_blk: stack used = 432
>
> Is it worth it to make the good compiler worse? People are going to use
> the newer GCC more as time goes on anyhow.

No, but it's only 16 bytes of stack loss for a simplicity win:

virtio_ring.c | 120 +++++++++++++++++++++-------------------------------------
1 file changed, 45 insertions(+), 75 deletions(-)

Cheers,
Rusty.