Re: reducing stack usage in v4l?
Daniel Jacobowitz (dan@debian.org)
Tue, 11 Mar 2003 10:36:49 -0500
On Tue, Mar 11, 2003 at 04:29:30PM +0000, Alan Cox wrote:
> On Tue, 2003-03-11 at 09:19, Gerd Knorr wrote
>
> > That is wrong, at least the 2k memset/call mentioned by Andrew. There
> > are lots of memset() calls, but they all are within the case switches
> > for the ioctls and zero out only the structs which are used in that code
> > path, so it is actually much smaller (~50 -> ~300 bytes maybe, depending
> > on the ioctl).
>
> gcc sometimes does things like allocate all the objects in case
> statements at entry time. I assume its a performance win to do so.
No, it's more likely a known GCC bug to do so. See PR middle-end/9997
if you're really curious.
--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer
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