On 06/07/2013 08:54 AM, Ren Mingxin wrote: > Hi, Hannes: > > On 06/06/2013 05:43 PM, Hannes Reinecke wrote: >> this is the first step towards a new non-blocking >> error handler. This patch implements a new command >> timeout handler which will be sending command aborts >> inline without engaging SCSI EH. >> >> In addition the commands will be returned directly >> if the command abort succeeded, cutting down recovery >> times dramatically. >> >> With the original scsi error recovery I got: >> # time dd if=/dev/zero of=/mnt/test.blk bs=512 count=2048 oflag=sync >> 2048+0 records in >> 2048+0 records out >> 1048576 bytes (1.0 MB) copied, 3.72732 s, 281 kB/s >> >> real 2m14.475s >> user 0m0.000s >> sys 0m0.104s >> >> with this patchset I got: >> # time dd if=/dev/zero of=/mnt/test.blk bs=512 count=2048 oflag=sync >> 2048+0 records in >> 2048+0 records out >> 1048576 bytes (1.0 MB) copied, 31.5151 s, 33.3 kB/s >> >> real 0m31.519s >> user 0m0.000s >> sys 0m0.088s >> >> Test was to disable RSCN on the target port, disable the >> target port, and then start the 'dd' command as indicated. >> >> As a proof-of-concept I've also enabled the new timeout >> handler for virtio, so that things can be tested out >> more easily. > > So this 31.5s is tested on virtio disks, right? Much faster than your > former test via fc. > No. This was done on HP Proliant /QLogic FC running against HP P2000. There is a reason why I posted this new patchset :-) (The old patchset had a bug where it wouldn't abort the TUR send by multipaths path-checker. Which were causing delays during switchover. This version now does terminate them properly) (Incidentally, it was the non-working scsi_noretry_cmd() which caused this bug :-) > This approach may not work for some LLDDs as you said, but I wonder > whether SAS is applicable(whether there will be later patches for > SAS). > SAS should be applicable for this, too. I'll check. Cheers, Hannes -- Dr. Hannes Reinecke zSeries & Storage hare@xxxxxxx +49 911 74053 688 SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: J. Hawn, J. Guild, F. Imendörffer, 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
