Date: Fri, 15 Jun 2018 16:36:25 -0700 From: bob prohaska <fbsd@www.zefox.net> To: Warner Losh <imp@bsdimp.com> Cc: Mark Millard <marklmi@yahoo.com>, "freebsd-arm@freebsd.org" <freebsd-arm@freebsd.org>, "Rodney W. Grimes" <freebsd-rwg@pdx.rh.cn85.dnsmgr.net>, bob prohaska <fbsd@www.zefox.net> Subject: Re: GPT vs MBR for swap devices Message-ID: <20180615233625.GA41147@www.zefox.net> In-Reply-To: <CANCZdfo8=amqT7M6Xn8NJrW-8spd0XdxjAYjs3F7LVsBUQtpsw@mail.gmail.com> References: <20180614175622.GC35161@www.zefox.net> <201806142110.w5ELAL0N046840@pdx.rh.CN85.dnsmgr.net> <20180615035225.GA37370@www.zefox.net> <CANCZdfoNasSpvEN-y3bzsDfWT=_atfp62AKvdpwK8bUQKi=bgA@mail.gmail.com> <20180615051527.GB37370@www.zefox.net> <834EA7A6-B567-436F-96B2-0C75FACA3FF9@yahoo.com> <20180615154334.GA39777@www.zefox.net> <CANCZdfoCA=E=Sh2X6H=Fi-TBkhiTdyzXAkjXr4usa8ie6%2Buo4g@mail.gmail.com> <20180615164202.GB39777@www.zefox.net> <CANCZdfo8=amqT7M6Xn8NJrW-8spd0XdxjAYjs3F7LVsBUQtpsw@mail.gmail.com>
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On Fri, Jun 15, 2018 at 11:21:01AM -0600, Warner Losh wrote: > On Fri, Jun 15, 2018 at 10:42 AM, bob prohaska <fbsd@www.zefox.net> wrote: > > > On Fri, Jun 15, 2018 at 09:57:17AM -0600, Warner Losh wrote: > > > > > gstat -Bd -I 10 -f <regexp for your swap partition> > > > gstat-swap-data.dat > > > Could a longer interval, maybe one or ten seconds, and perhaps the -a flag to reduce file size produce useful results? Given the way gstat output is formatted it does not look easy to search, except in small amounts by eye. > > > would be how I'd recommend collecting it. This file may get kinda big > > > depending how long it takes to trigger the weird state. I'm hoping that > > if > > > you put this on a known good device, we'll power through the issues. We > > > might not get perfect correlation with this, but the data should show all > > > kinds of crazy before the system drives off the cliff if I'm right, so we > > > don't need perfect data. > > > > > > > Apologies, we spoke of gstat earlier. I lost the distinction between > > gstat and vmstat. In the case at hand the possible swap devices are > > > > /dev/da0b (this is the one causing trouble) > > /dev/mmcsd0s3b > > /dev/mmcsd0s3d > > > > > > what would the correct <regexp> look like? > > > > I'd just use -f '^da0b$' for each of the devices. > So, ignore the SD flash for now? > > > Is there any indication why problems seen on the RPI3 do not seem > > apparent on an RPI2? A 2 GB USB flash swap partition seems to work > > successfully on the Pi2. > > > > Interesting. The only thing I can think of is different OOM tuning levels. > But if anything, I'd expect more trouble on the RPi2 than the RPi3. So that > might also point to a difference in USB and/or VM things. It would be > interesting to see if we see a significant difference in the graphs between > the two for the same physical drive. I'd have expected, like you, that this > would be reproducible between the two. > The Pi2 vs Pi3 comparison is less fair than I indicated; the Pi2 is running 11.2-PRERELEASE FreeBSD 11.2-PRERELEASE #0 r335072, while the Pi3 is running 12.0-CURRENT FreeBSD 12.0-CURRENT #0 r334939. Both Pi2 and Pi3 are using 64 GB Sandisk Extreme USB flash drives, but the unit on the Pi3 is about a year newer. I'd expect that to help, rather than hurt, but.... I'll try logging gstat output on the Pi2 as-is during a clean-start buildworld and see what happens. Thanks for all your help! bob prohaska
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