Alan Stern wrote: > On Fri, 2 Mar 2007, Gordon Messmer wrote: > > The first thing to note is that the second column is a timestamp, with > time values recorded in microseconds. That tells us the time interval > between I/O errors (rounded off to the nearest second):
I know. :) > The patch could shorten the time window from 2 seconds to 0.5 seconds. > That would reduce the number of spurious resets even more, but it wouldn't > eliminate them entirely. And it wouldn't eliminate the IO errors the way that booting up and old kernel does. > I don't see any regular pattern in those time intervals, do you? Well, no, not now. However, when the problem originated, it was very reliably 10 seconds of idle before it froze. Or 90. It depended on which kernel I was running. I didn't know about usbmon a year ago or I would have had more information. Maybe I can boot up one of those old FC5 kernels and see what happens. Even now, there are periods where the timing is fairly stable, and I could be convinced that it was regular if I didn't watch it long enough. I did a quick check this morning and saw a short sequence of IO error, 25 second delay, reset, 8 second delay, repeat (example is attached). But after a few cycles, the timing became more erratic. > Which > leads me to think the cause is something more or less random, like > electromagnetic interference. Do you think the interference could be one motherboard component interfering with another? Perhaps one that wasn't supported, or was handled in a different manner under earlier kernels? > It's probably not a software entity > periodically doing something bad. > > But of course that doesn't explain why the effect fails to show up at all > with the earlier kernel... Yeah, that one bit is what makes it hard to form a theory that states that the kernel isn't involved somehow. Every time I boot up 2.6.17, the system is fine. Or, at least, it is very quiet about any errors that may happen. It's a hell of a mystery. I've tried building the new kernel using the old kernel's .config to eliminate configuration changes. I noticed that the new kernel uses CONFIG_HZ_1000, where the old one used CONFIG_HZ_250. There's also CONFIG_USB_EHCI_TT_NEWSCHED set in the new kernel. When the kernel was built with the old configuration, the resets and IO errors were still present. I wonder if I could install FC4 on this host and use an FC6 kernel. I continue to be grateful for your assistance in looking at this. It may be just a hardware flaw exposed by changes in the kernel, but it's a confounding mystery to me, and I hate those. Sample sequence with more or less regular timing: f7e786c0 171193090 C Ii:003:01 -84 0 f7e786c0 171206079 S Ii:003:01 -115 4 < f7e786c0 195840314 C Ii:003:01 -84 0 f7ca54c0 195840340 S Co:001:00 s 23 03 0004 0001 0000 0 f7ca54c0 195840344 C Co:001:00 0 0 f7ca54c0 196041329 S Ci:001:00 s a3 00 0000 0001 0004 4 < f7ca54c0 196041336 C Ci:001:00 0 4 = 03030000 f7ca54c0 196092320 S Co:001:00 s 23 01 0014 0001 0000 0 f7ca54c0 196092325 C Co:001:00 0 0 f7ca54c0 196092340 S Ci:000:00 s 80 06 0100 0000 0040 64 < f7ca54c0 196099304 C Ci:000:00 0 18 = 12011001 00000008 6d040cc0 10060102 0001 f7ca54c0 196099317 S Co:001:00 s 23 03 0004 0001 0000 0 f7ca54c0 196099321 C Co:001:00 0 0 f7ca54c0 196300279 S Ci:001:00 s a3 00 0000 0001 0004 4 < f7ca54c0 196300286 C Ci:001:00 0 4 = 03030000 f7ca54c0 196351271 S Co:001:00 s 23 01 0014 0001 0000 0 f7ca54c0 196351276 C Co:001:00 0 0 f7ca54c0 196351280 S Co:000:00 s 00 05 0003 0000 0000 0 f7ca54c0 196353297 C Co:000:00 0 0 f7ca54c0 196366266 S Ci:003:00 s 80 06 0100 0000 0012 18 < f7ca54c0 196371297 C Ci:003:00 0 18 = 12011001 00000008 6d040cc0 10060102 0001 f7ca54c0 196371306 S Ci:003:00 s 80 06 0200 0000 0022 34 < f7ca54c0 196379300 C Ci:003:00 0 34 = 09022200 010100a0 32090400 00010301 02000921 10010001 22440007 05810308 f7ca54c0 196379314 S Co:003:00 s 00 09 0001 0000 0000 0 f7ca54c0 196382293 C Co:003:00 0 0 f7ca54c0 196382301 S Co:003:00 s 01 0b 0000 0000 0000 0 f7ca54c0 196385294 C Co:003:00 0 0 f7ca54c0 196385408 S Co:003:00 s 21 0a 0000 0000 0000 0 f7ca54c0 196388300 C Co:003:00 0 0 f7e786c0 196388316 S Ii:003:01 -115 4 < f7e786c0 203544076 C Ii:003:01 -84 0 f7e786c0 203556889 S Ii:003:01 -115 4 < f7e786c0 228807278 C Ii:003:01 -84 0 f2a8eac0 228807306 S Co:001:00 s 23 03 0004 0001 0000 0 f2a8eac0 228807310 C Co:001:00 0 0 f2a8eac0 229008019 S Ci:001:00 s a3 00 0000 0001 0004 4 < f2a8eac0 229008026 C Ci:001:00 0 4 = 03030000 f2a8eac0 229059010 S Co:001:00 s 23 01 0014 0001 0000 0 f2a8eac0 229059015 C Co:001:00 0 0 f2a8eac0 229059029 S Ci:000:00 s 80 06 0100 0000 0040 64 < f2a8eac0 229065268 C Ci:000:00 0 18 = 12011001 00000008 6d040cc0 10060102 0001 f2a8eac0 229065278 S Co:001:00 s 23 03 0004 0001 0000 0 f2a8eac0 229065283 C Co:001:00 0 0 f7ca54c0 229265967 S Ci:001:00 s a3 00 0000 0001 0004 4 < f7ca54c0 229265974 C Ci:001:00 0 4 = 03030000 f7ca54c0 229316959 S Co:001:00 s 23 01 0014 0001 0000 0 f7ca54c0 229316964 C Co:001:00 0 0 f7ca54c0 229316968 S Co:000:00 s 00 05 0003 0000 0000 0 f7ca54c0 229319261 C Co:000:00 0 0 f7ca54c0 229331955 S Ci:003:00 s 80 06 0100 0000 0012 18 < f7ca54c0 229337265 C Ci:003:00 0 18 = 12011001 00000008 6d040cc0 10060102 0001 f7ca54c0 229337281 S Ci:003:00 s 80 06 0200 0000 0022 34 < f7ca54c0 229345265 C Ci:003:00 0 34 = 09022200 010100a0 32090400 00010301 02000921 10010001 22440007 05810308 f7ca54c0 229345278 S Co:003:00 s 00 09 0001 0000 0000 0 f7ca54c0 229348258 C Co:003:00 0 0 f7ca54c0 229348266 S Co:003:00 s 01 0b 0000 0000 0000 0 f7ca54c0 229351257 C Co:003:00 0 0 f7ca54c0 229351370 S Co:003:00 s 21 0a 0000 0000 0000 0 f7ca54c0 229354264 C Co:003:00 0 0 f7e786c0 229354282 S Ii:003:01 -115 4 < f7e786c0 236415040 C Ii:003:01 -84 0 f7e786c0 236428592 S Ii:003:01 -115 4 < f7e786c0 260702275 C Ii:003:01 -84 0 f24993c0 260702303 S Co:001:00 s 23 03 0004 0001 0000 0 f24993c0 260702308 C Co:001:00 0 0 c1df44c0 260742943 C Ii:001:01 0 1 = 02 c1df44c0 260742950 S Ii:001:01 -115 2 < f24993c0 260902911 S Ci:001:00 s a3 00 0000 0001 0004 4 < f24993c0 260902933 C Ci:001:00 0 4 = 03030000 f24993c0 260953902 S Co:001:00 s 23 01 0014 0001 0000 0 f24993c0 260953907 C Co:001:00 0 0 f24993c0 260953921 S Ci:000:00 s 80 06 0100 0000 0040 64 < f24993c0 260960265 C Ci:000:00 0 18 = 12011001 00000008 6d040cc0 10060102 0001 f24993c0 260960273 S Co:001:00 s 23 03 0004 0001 0000 0 f24993c0 260960277 C Co:001:00 0 0 c1df44c0 260992895 C Ii:001:01 0 1 = 02 c1df44c0 260992902 S Ii:001:01 -115 2 < f24993c0 261160862 S Ci:001:00 s a3 00 0000 0001 0004 4 < f24993c0 261160883 C Ci:001:00 0 4 = 03030000 f24993c0 261211852 S Co:001:00 s 23 01 0014 0001 0000 0 f24993c0 261211857 C Co:001:00 0 0 f24993c0 261211862 S Co:000:00 s 00 05 0003 0000 0000 0 f24993c0 261214259 C Co:000:00 0 0 f24993c0 261226851 S Ci:003:00 s 80 06 0100 0000 0012 18 < f24993c0 261232262 C Ci:003:00 0 18 = 12011001 00000008 6d040cc0 10060102 0001 f24993c0 261232278 S Ci:003:00 s 80 06 0200 0000 0022 34 < f24993c0 261240265 C Ci:003:00 0 34 = 09022200 010100a0 32090400 00010301 02000921 10010001 22440007 05810308 f24993c0 261240279 S Co:003:00 s 00 09 0001 0000 0000 0 f24993c0 261242841 C Co:003:00 0 0 f24993c0 261242852 S Co:003:00 s 01 0b 0000 0000 0000 0 f24993c0 261245256 C Co:003:00 0 0 f24993c0 261245369 S Co:003:00 s 21 0a 0000 0000 0000 0 f24993c0 261248261 C Co:003:00 0 0 f7e786c0 261248274 S Ii:003:01 -115 4 < ------------------------------------------------------------------------- Take Surveys. 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