Vladislav Bolkhovitin wrote: > Christoph Hellwig, on 08/05/2010 11:50 PM wrote: >> On Thu, Aug 05, 2010 at 11:48:19PM +0400, Vladislav Bolkhovitin wrote: >>> So, I believe, Linux must use that possibility to get full storage >>> performance and to finally simplify its storage stack. >> >> So instead of talking what about doing a prototype and show us what >> improvement it gives? > > Sure, I'd love to. But, unfortunately, I can't clone myself, so I'm > trying to help the best of what I could: my level of storage and SCSI > expertise. This area is quite special, so I'm trying to explain some > misunderstandings I see and illustrate my points by some possible work > flows and interfaces. > I can't, neither. But I can do bonnie runs in no time. I have done some preliminary benchmarks by just enable ordered queueing in sd.c and no other changes. Bonnie says: Writing intelligently: 115208 vs. 82739 Reading intelligently: 134133 vs. 129395 putc() performance suffers, though: I get 52M vs 90M writing and 50M vs. 65M reading. No idea why; shouldn't be that harmful here. But in any case there is some speed improvement to be had from using ordered tags. Oh, and that was against an EVA 6400. Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@xxxxxxx +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Markus Rex, HRB 16746 (AG Nürnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
