-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 03/01/2012 12:50 PM, Jim Meyering wrote: > > Hi Phillip, > > Can you describe, or better still, tell me how to demonstrate the > problem this is fixing? Or can you at least give a few details, like > which kernel you used, which command invoked and which values you got > for the two *_io variables?
I have a server with a 4 disk mdadm raid5 that has an optimal value of 1.5 MiB as a result of the 512k stripe factor. The current default stripe factor is 512k but it used to be 64k. If you used a 64k stripe factor that would give an optimal value of 192k with a 4 disk raid5. > I think your description was somehow negated, since it's the reverse > actually: it accepts a nonzero kernel alignment A only if 2^20 % A == 0. > I.e., that requires A<= 1024^2. A kernel alignment value larger > than 1024^2 is ignored. You are right, the comment was wrong. Try this instead: There were several apparently incorrect tests that would cause the kernel supplied optimal io size to be discarded in favor of the default 1 MiB alignment. As written, it would only accept values less than the parted default ( 1 MiB ) that were also an even power of two. For example, 128k or 512k would be accepted, but 192k or 1.5 MiB would be ignored. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJPVXPSAAoJEJrBOlT6nu75r5gIAKGcTdC9K56OqRL5LreQN/2m xDAjinieAMH5DNHMiYGflvQUOch2w02UIkYZZJFm+rloWr4APAokNYPRAvQoDGh8 ZajuWsvrcCJWRgkg2umuZRP0gOpsa7ZDUfOfYESR4AR4VgXUSfTmtcW4KFaVSuD0 0sLyYYlV17Vp28H12AQVn/5qynmM1k/JzU3CsTElWLAV0lB4Wx7B9HO/uvYbIO7H c6sg6gwHFoBTmhUWr01Ldx+6yhj3BucspSCpP1mJmGEUhHX92rgz5UN6xd2k01+v pdT8sYkHQNlLBFB0CHthhCSBRoErb0HIjF3ipGEnoLXtfh7TxMO1szoFVILcGq0= =Cekr -----END PGP SIGNATURE-----
