On Thu, 27 Jan 2005, Robert Watson wrote: > While it's not for the feint of heart, it might be interesting to see > how results compare in 6-CURRENT + debugging of various sorts (including > malloc) turned off, and debug.mpsafevfs turned on. One possible issue > with the twe/twa drivers is that they are currently MPSAFE, so may see > substantial contention (and hence additional latency). The move to an > MPSAFE VFS will help with that a lot, I should think.
And, if you're in the mood for hacking code, and promise not to use snapshots, try making vfs_subr.c:vn_start_write(), vfs_subr.c:vn_write_suspend_wait(), vfs_subr.c:vn_finished_write(), vfs_subr.c:vfs_write_suspend(), and vfs_subr.c:vfs_write_resume() into noop's. These calls are used to avoid some deadlock scenarios associated with snapshot generation, but they also introduce a small but non-trivial amount of overhead to a number of operations. Since you're set up to do some testing, knowing how much of that cost is from these operations should be quite interesting. Robert N M Watson _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
