Hello, Quoting Jeff Dike <[EMAIL PROTECTED]>:
> Sorry about the lack of responsiveness. No problem, I'm glad to read you now. > I've had such a patch for quite a while. I never stuck it in mainline > because I couldn't find any common use cases where it made a noticable > difference. > > Does your patch help noticably with anything reasonable common? It did help significantly for me. On a reasonably new host, using as UBD devices logical volumes built on top of a FC SAN, building a 10GB ext3 filesystem took something like 50 seconds before my patch, and something like 3 seconds after it. (I can check the exact values if you wish.) Note that this is using CONFIG_UBD_SYNC (or whatever it is called); without it it gets even faster (but I guess parallel I/O make no difference). My feeling is that it might improve performance when reads and writes are performed simultaneously, but I have not made any try. As for using CONFIG_UBD_SYNC, my feeling is that it's much safer if the host might crash (or experience power outages, or...): as far as I understand it, journaled filesystems need to know when data is actually secured on the discs. Hope this helps, Nicolas Boullis Ecole Centrale Paris ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
