Hi all, I'd like to propose a topic on block-mq issues with FC. During my performance testing using block/scsi-mq with FC I've hit several issues I'd like to discuss:
- timeout handling: Out of necessity the status of any timed out command is undefined. So to be absolutely safe HBAs will be using extended timeouts here (eg 70secs for lpfc). During that time we _could_ signal I/O timeout to the upper layers, but then the tag will be reused, despite the HBA still having a reference to it. I'd like to discuss how this could be solved best with blk-mq. - Adaption on other HBAs to multiqueue: The current block-mq design assumes symmetric send and receive queues (in effect queue pairs). Any hardware _not_ providing this (like qla2xxx) can not be easily converted to scsi-mq. I'd like to discuss how one could approach converting these drivers. Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking [email protected] +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 [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
