Hi Weikuan, I handle most of the IOR maintenance, and I agree the FILE_DELIMITER needs to be changed from ':' to something else. The '@' change seems a good fit for IOR users in the past who've had problems with ':', so I'll update the source to reflect this new default.
As for the time drift, I think the time drift between nodes should be calibrated so all nodes see the same starting time. Currently, IOR has ignored recalibrating if the skew is less than 5 seconds between the earliest and latest times. If the skew is too egregious (> 5), then all tasks use the root task's time. I agree that a better approach would be to have IOR adjust for time drift without regard to the wallclock outlier threshold. I'll make this change. Also, I am going to remove the "WARNING: Time deviation . . ." message. (I agree it can be annoying.) I will leave the "Wall clock deviation: X.Y sec", however. There are cases where we need to see how badly the nodes are out of synchronization timewise. I don't think this is too intrusive to the output. If you have any follow up comments to the lustre-discuss list on these changes or IOR in general, please cc me as well. Thanks, -- Bill. > Date: Fri, 09 Feb 2007 08:59:08 -0500 > From: Weikuan Yu <[EMAIL PROTECTED]> > To: lustre <[email protected]> > Subject: [Lustre-discuss] IOR patch > > Hi, > > I could not find a IOR list. Figured that there are a lot of folks on this > list are using IOR, who might be interested. Here is a patch to eliminate > two oversights of IOR. > > 1) Conflict in the usage of FILE_DELIMITER ':' > 2) Inaccurate reports due to any drift in time > > Note: > -- ':' is already taken by ROMIO for long for specifying file system > type. By replacing it with '@', the problem is solved. File system > specification is again possible. > -- Time drift is an annoying problem of IOR. IOR checks on the skew > of timestamps from each process. But it does not calibrate the timer at > the beginning. So it spews numerous warning on systems with big drift > across nodes. In addition, it reports wrong numbers for IO rate. Added > recalibration still makes your numbers more accurate, even if you did not > notice you have a problem before. > > Let me know if you may have some comments. > > Thanks, > Weikuan > ++++++++++++++++++++++++++++ > Weikuan Yu <+> 1-865-574-7990 > http://www.csm.ornl.gov/~wyu/ _______________________________________________ Lustre-discuss mailing list [email protected] https://mail.clusterfs.com/mailman/listinfo/lustre-discuss
