Date: Fri, 20 Dec 2024 11:54:10 -0800 From: bob prohaska <fbsd@www.zefox.net> To: Mark Millard <marklmi@yahoo.com> Cc: freebsd-arm@freebsd.org Subject: Re: armv7, silent hang, low swap, high priorities Message-ID: <Z2XLYmOFoQ6wYw_X@www.zefox.net> In-Reply-To: <633E900F-9C67-4956-A628-3A1549A40AF8@yahoo.com> References: <Z2Wk8DRQjEdygNlW@www.zefox.net> <633E900F-9C67-4956-A628-3A1549A40AF8@yahoo.com>
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On Fri, Dec 20, 2024 at 09:24:10AM -0800, Mark Millard wrote: > On Dec 20, 2024, at 09:10, bob prohaska <fbsd@www.zefox.net> wrote: > > > An old (v 1.1) Pi2 running armv7 -current often hangs during buildworld. > > > > It doesn't respond to enter-tilda-control-B and has to be powercycled. > > Once rebooted, buildworld can be restarted and makes further progress, > > sometimes to completion. Swap was configured in two partitions, one > > on microSD and one on mechanical hard disk, thus both over-provisioned > > and wildly unequal in speed. Root is on the mechanical disk. > > > > An orphan top window surprised me by reporting very high priorities > > in the 130 range but swap usage was relatively low, less than 100MB. > > That seemed an odd combination. Usually priorities that high are > > associated with severe memory pressure. Could the mismatched swap > > speeds have confused the scheduler? There were no console warnings. > > > > The machine was fully loaded with a -j4 buildworld, so the fact of > > the hang isn't hugely surprising. The top display, at > > http://www.zefox.net/~fbsd/rpi2/crashes/20241219/top_display > > seemed internally inconsitent. Does it surprise anybody else? > > > > I've since removed the microSD swap, leaving only the mechanical disk > > swap, to see if that changes the hang behavior. > > > QUOTE > . . . > The nice utility runs utility at an altered scheduling priority, by in- > crementing its "nice" value by the specified increment, or a default > value of 10. The lower the nice value of a process, the higher its > scheduling priority. > END QUOTE > > Renice, setpriority(), etc. agree. > > Those 120+ figures are LOWER priority than the under 100 figures, > not higher. It never occurred to me that "PRI" might be in units of niceness. Thank you! bob prohaska
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