Date: Fri, 13 Jul 2007 16:43:25 +0800 From: "Li-Lun Wang (Leland Wang)" <llwang@infor.org> To: freebsd-current@freebsd.org Subject: threadlock and msk watchdog timeout Message-ID: <20070713084325.GA47351@Athena.infor.org>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, After making world a couple of days ago, my msk(4) became very unstable. Under moderate network load, the interface hung and I received kernel: msk0: watchdog timeout (missed Tx interrupts) -- recovering at least once every several minutes and kernel: msk0: Rx FIFO overrun! occasionally. It was so annoying that I took the trouble of binary searching the kernel version to find the one destabilized my msk(4). The outcome of the search turned out te be strange. Instead of finding a date after which msk(4) became so very unstable, it *seemed* that the older the kernel version the stabler msk(4) I got, and the newer the kernel version the easier and more often msk(4) hung. I managed to pin down that with the kernel as of 2007.06.04.12.00.00, it seemed not to give me any msk watchdog timeout at all, and that with the kernel as of 2007.06.05.12.00.00, msk(4) began to hang and the watchdog began to timeout once in a while. There may be a latter commit that made my msk(4) even more unstable, but I am not sure about this part as it is not easy to measure the level of "unstableness" of the network. It seems that the most significant commit between 2007.06.04.12.00.00 and 2007.06.05.12.00.00 was threadlock by jeff@. I don't know why or how it would affect msk(4), though. I was using SCHED_SMP on a C2D, but switched back to SCHED_ULE when I did the search. I discovered a couple other funny phenomena during the search that may also suggest this be related to threadlock. One is that msk(4) seemed to hang less frequently when the system was busy building world or kernel. The other thing is that I seemed to be able to help unhang the interface by switching the input focus in X Window by move my mouse cursor to another window. My result might not be accurate, though, as I only rebuilt the kernel, not the whole world, when I did the search. - -- llwang -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.3 (FreeBSD) iD8DBQFGlzseCQM7t5B2mhARAiKNAJ9wwCRBFGQOo5Vy2pzTrldHwHh3zwCfXw/u NZ66KfvJ0HR1A2sc/HffwxI= =fi7k -----END PGP SIGNATURE-----
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