On Sat, 26 Jul 2008, Richard Elling wrote: > > Is it doing buffered or sync writes? I'll try it later today or > tomorrow...
I have not seen the source code but truss shows that this program is doing more than expected such as using send/recv to send a message. In fact, send(), pollsys(), recv(), and write() constitute most of the activity. A POSIX.4 real-time timer is created. Perhaps it uses two threads, with one sending messages to the other over a socketpair, and the second thread does the actual write. >> I did not run your program in a real-time scheduling class (see priocntl). >> Perhaps it would perform better using real-time scheduling. It might also >> do better in a fixed-priority class. > > This might be more important. But a better solution is to assign a > processor set to run only the application -- a good idea any time you > need a predictable response. Later on I did try running the program in the real time scheduling class with high priority and it made no difference at all. While it is clear that filesystem type (ZFS or UFS) does make a significant difference, it seems that the program is doing more than simply timing the write system call. A defect in the program could easily account for the long delays. It would help if source code for the program can be posted. Bob ====================================== Bob Friesenhahn [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
