On 07/08/2013 06:53 AM, NeilBrown wrote: > On Sun, 07 Jul 2013 19:39:27 +0200 Milan Broz <gmazyland@xxxxxxxxx> wrote: > > >> So if you have multiple IOs submitted in parallel from *different* CPUs, >> they are processed in parallel. >> >> If you have MD over dmcrypt, this can cause problem that MD sumbits all IOs >> with the same cpu context and dmcrypt cannot run it in parallel. > > For RAID1 and RAID10 this isn't true any more. > > Commit f54a9d0e59c4bea3db733921ca9147612a6f292c > in 3.6 changed this for RAID1 and a similar commit did for RAID10. > RAID4/5/6 still submit from a single thread as you say. Ah, sorry, missed that change, thanks Neil! So then it should perform much better. (But IIRC most reports about dmcrypt performance was either over high-speed SSD without AES-NI or over RAID5 - case like huge ftp archive where they need redundancy & offline data security. But here current design should be help...) Milan -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
