Extremely poor performance crunching random numbers under PIV-FC5

Jakub Jelinek jakub at redhat.com
Fri May 19 15:00:07 UTC 2006


On Fri, May 19, 2006 at 03:54:26PM +0100, Matt Davey wrote:
> On Fri, 2006-05-19 at 10:20 -0400, Jakub Jelinek wrote:
> > On Fri, May 19, 2006 at 04:16:40PM +0200, BankHacker wrote:
> > > Jakub, I have tried to do what you propose but the following code is
> > > throwing an error in execution time:
> [...]
> > > 		memset(randomdataState, 0, sizeof(*randomdataState));
> > 
> > And you dereference the uninitialized pointer here ^^^.
> 
> Umm, just to be pedantic, sizeof will happily return
> the number of bytes required to store 'struct random_data'.  It doesn't
> need to dereference anything.  eg. "sizeof(struct random_data)"

The problem is already in that memset, not on the third memset
argument, but the first.  The dereference is done in memset, not in the
caller.

	Jakub




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