On Tue, Jan 25, 2005 at 02:27:57PM +0000, Christoph Hellwig wrote: > > It is not the driver per se, but the way the memory which is the I/O > > source/target is presented to the driver. In linux there is a good > > chance it will have to use more scatter gather elements to represent > > the same amount of data. > > Note that a change made a few month ago after seeing issues with > aacraid means it's much more likely to see contingous memory, > there were some numbers on linux-scsi and/or linux-kernel.
But only at the beginning. iirc after a few days of uptime and memory fragmentation it degenerates back to the old numbers. Perhaps the recent anti defragmentation work will help more. -Andi P.S.: on a AMD x86-64 box the theory can be relatively easily tested: just run with iommu=force,biomerge that will use the IOMMU to merge SG elements. I just don't recommend it for production because some errors are not well handled. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
