>>>> Paul Warren <[EMAIL PROTECTED]> 02/09/05 10:31AM >>> > A delay. My original question was, does using tempfs do more than > prevent the memory from getting swapped out? We have developed a patch > that mlock()s the memory (using a setuid helper app), and thus should > stop it from getting swapped out. Would using tempfs improve things > further?
If you already have it mlock(), I doubt it. I had missed this fact in the original messages. > We've disabled this. Having searched the archives, I believe the > summary is: > > CONFIG_BLK_DEV_UBD_SYNC == YES => All I/O is synchronous and slow > CONFIG_BLK_DEV_UBD_SYNC == NO => I/O is synchronous if you use ubds= on > the command line, and the synchronous behaviour is implemented in a > faster way than if you use the config option. > > So, you should never use this config option, even if you want all I/O to > be synchronous - you're better off using ubds= Interesting. I was under the impression that the differences, if any, were now mute. However, now that I'm reviewing the archives, the closest reference I can find is this: http://sourceforge.net/mailarchive/message.php?msg_id=10657257 Authoritative clarification would be greatly appreciated! > On a related note, has anyone tried using LVM logical volumes as root > devices for UML guests? My expectation is that this would improve I/O > performance as writes do not need to go through two layers of > journalling filesystem, but I'd be interested to know if anyone has > tried it or if there is any reason why this is a bad idea. I'm also interested in this. I was going to play with this a few weeks ago but haven't had the time. Tony ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click _______________________________________________ User-mode-linux-user mailing list User-mode-linux-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
