On 04/13/2016 08:07 PM, Tejun Heo wrote: > On Tue, Apr 12, 2016 at 08:47:49AM +0200, Hannes Reinecke wrote: >> Recent devices can use NCQ encapsulation for READ LOG DMA EXT, >> so we should be using it if available. > > Does this have any actual benefits than being new and shiny? It's > being called from EH path where we know that no other commands are in > flight. > Hehe. No, it isn't, if you look closely. (Or make that: it _shouldn't_, and I've messed it up) (That's what the 'fpdma' parameter is for)
The benefit is not so much for normal operations, but it'll give us a performance improvements on SMR drives where we need to issue READ LOG DMA EXT rather frequently. There we really want to have them as NCQ commands. Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking h...@suse.de +49 911 74053 688 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton HRB 21284 (AG Nürnberg) -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
