On Tue, Apr 17, 2018 at 04:55:51PM +0100, Alan Jenkins wrote: > On 17/04/18 08:21, Johannes Thumshirn wrote: > > On Mon, Apr 16, 2018 at 10:52:47PM +0100, Alan Jenkins wrote: > > > > Without this fix, I get an IO error in this test: > > > > > > > > # dd if=/dev/sda of=/dev/null iflag=direct & \ > > > > while killall -SIGUSR1 dd; do sleep 0.1; done & \ > > > > echo mem > /sys/power/state ; \ > > > > sleep 5; killall dd # stop after 5 seconds > > > linux-block insisted they wanted this, based on my reproducer above. > > > If you start wondering why you wouldn't base it on scsi_debug with a new > > > "quiesce" option, that makes two of us. > > Thanks for doing this: > > > + # Maybe annoying for Xen dom0, but I'm guessing it's not common. > > > + if grep -q ^flags.*\ hypervisor /proc/cpuinfo && > > > + (( !HAVE_BARE_METAL_SCSI )); then > > > + SKIP_REASON=\ > > > +"Hypervisor detected, but this test wants bare-metal SCSI timings. > > > +If you have a pass-through device, you may set HAVE_BARE_METAL_SCSI=1." > > > + return 1 > > > + fi > > I don't think we need this, if people want to shoot themselves in the > > foot by runnning a possibly destructive test suite in a HV we > > shouldn't stop them. > > Thanks, this is what I was hoping to get discussion on :). > > What is meant by HV? Hypervisor, sorry. > > This is phrased to solve a problem I hadn't mentioned previously: > > + # I can't expect to hit the window using bash, if the device is > + # emulated by cpu. > > I haven't tested this reproducer against devices emulated in software. It's > written against real hardware which takes a whole second to bring the SATA > link up. (And maybe spin up the hdd as well?). > > I'm not familiar with linux-block's testing, to know how prevalent that > bare-metal access is. I would like to avoid putting out a lot of "pass" > where it's effectively being skipped. > > (The comment you did quote just refers to this check being annoying in dom0, > because I assume the check detects dom0 as being virtualized, despite it > having access to bare-metal scsi devices. It's not a great comment; I will > clarify it a bit). > > Yes, if this reason turns out to be marginal, I would be back to the concern > about reliability of VM suspend, and wanting it to be opt-in with > DO_PM_TEST=1 in the config file or something. As a newb to blk-tests I > would be very frustrated to spin up virt-manager with a virtual test device, > because I would run into what turns out to be an unfixed kernel bug. Well it's a test result as well, isn't it ;-). I personally run all my testing in VMs (with optional PCI passthrough if I need special Hardware). But yes this is just my personal preference. > I'm happy to have the simpler check for DO_PM_TEST (with more verbose > SKIP_REASON) if it works; maybe the autodetection just made extra > complexity. > > > + > > > + _have_fio > > Not needed anymore as per below comment? > > Good point, yes (but see below). > > > > + # I tried using fio with the exact same IO pattern, > > > + # sadly it was not 100% reliable at reproducing this > > > + # issue. > > > + # > > > + dd iflag=direct if="$TEST_DEV" of=/dev/null bs=$bs status=none & > > > + dd_pid=$! > > > + > > > +# fio --output="$FULL" --loops=65535 \ > > > +# --thread --exitall_on_error \ > > > +# --direct=1 \ > > > +# --bs=$bs --rw=read --name=reads \ > > > +# --filename="$TEST_DEV" & > > > +# fio_pid=$! > > I think we can just zap the commented out fio part and the comment > > about it. > > fio was attractive as a way to avoid the failure case for ludicrously > small/fast devices. Later I actually hit that case, from running this test > on a small unused partition :). > > I think I've worked out the reliability now. So I can start using fio, and > have a solid answer to both issues. OK Thanks, Johannes -- Johannes Thumshirn Storage jthumshirn@xxxxxxx +49 911 74053 689 SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg GF: Felix Imendörffer, Jane Smithard, Graham Norton HRB 21284 (AG Nürnberg) Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850
