On 03/09/2011 09:11 AM, Thomas Damgaard wrote: > I have recently switched from i386 to amd64. After switching to 64 > bit, I/O on LUKS encrypted devices became horribly slow. > Do you have any idea what causes this? Or suggestions on how to debug > this further? > > I have submitted a bug report on this on Launchpad. The report > includes details on performance, hardware, etc. Well, seems you already proved the it is Ubuntu kernel only problem. So generic suggestions - be sure that - you are always using the same encryption parameters (cipher, key size) (once device is unlocked, performance is kernel only thing, so this cannot be cryptsetup/LUKS problem) - if you are testing fs over dmcrypt, be sure the same fs with the *same* mount parameters is used. If using barriers switch them off for test. (barrier=0). Verify with dmesg log. - check which kernel cryptoAPI module is used for the encryption (kernel should load arch sepcific one, e.g. aes_x86_64 vs aes_i586, not generic one). usually simple lsmod of loaded modules here gives you hint. Try blacklist that module so generic one is used etc. - try some new kernel, I think even Ubuntu provides upstream snapshots There is no reason x86_64 should be slower - many people it using, even on the same hw you have. Milan _______________________________________________ dm-crypt mailing list dm-crypt@xxxxxxxx http://www.saout.de/mailman/listinfo/dm-crypt
