Rob van der Heij wrote: > Those are orders of binary magnitude? :-) And half of that is ? Ask someone who works on performance. I do never publish measurements taken on my guest.
> The thing I really like about swapping to DCSS is that you don't drop > out of SIE and avoid going through CP and be questioned on whether you > can continue. I would still need a good experiment to show that > benefit (other than being able to swap faster). > The official word of Velocity is that we believe the advantage at > common swap rates do not outweigh the complexity of hacking mem= and > the risk of getting it wrong on some systems. The major benefit is _not_ related to direct mem-mem copy or SIE intercepts. As opposed to the dasd device driver, which is optimized for real disk IO, we have done quite a few optimizations to our dcss block device driver that makes it fit perfect for virtual devices: - no request building/merging - no device plug mechanism - no IO schedulers - no start subchannel and interrupt semantics - just synchronous memcopy Carsten -- Carsten Otte IBM Linux technology center ARCH=s390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
