On 09.04.2018 19:10, Peter Maydell wrote: > My NetBSD build system recently seems to have taken a nosedive > in how long it takes to finish "make check". This seems to be > because qom-test (and probably other things where the test interacts > with the QEMU process) can run very slowly. > > netbsdvm# for i in 1 2 3 4 5 6 7 8 9 10; do > (QTEST_QEMU_BINARY=x86_64-softmmu/qemu-system-x86_64 time > tests/qom-test -p /x86_64/qom/pc-i440fx-2.0); done > /x86_64/qom/pc-i440fx-2.0: OK > 8.49 real 1.18 user 7.34 sys > /x86_64/qom/pc-i440fx-2.0: OK > 10.41 real 1.32 user 9.09 sys > /x86_64/qom/pc-i440fx-2.0: OK > 8.45 real 1.24 user 7.24 sys > /x86_64/qom/pc-i440fx-2.0: OK > 9.88 real 1.10 user 8.31 sys > /x86_64/qom/pc-i440fx-2.0: OK > 11.60 real 1.47 user 9.90 sys > /x86_64/qom/pc-i440fx-2.0: OK > 10.94 real 1.28 user 9.68 sys > /x86_64/qom/pc-i440fx-2.0: OK > 10.06 real 1.32 user 8.76 sys > /x86_64/qom/pc-i440fx-2.0: OK > 13.38 real 1.37 user 12.04 sys > /x86_64/qom/pc-i440fx-2.0: OK > 16.19 real 1.46 user 14.29 sys > /x86_64/qom/pc-i440fx-2.0: OK > 9.70 real 1.17 user 8.51 sys > > Admittedly this is running in a (KVM) VM, but still, there seems > something wrong with how long each of these is taking. On Linux > each run is less than a second, so there's an order-of-magnitude > slowdown here. Further, I've occasionally seen a run take 100 seconds! > > Does anybody else see this, and any ideas why it might be running slow? > I'm not very familiar with debugging on netbsd; I had a look at > ktrace output, and the QEMU process seems to sometimes spend > quite a lot of time in a poll() loop not actually doing anything. > I couldn't figure out how to get the ktrace logs to annotate > which thread was making which syscall though, so they weren't > easy to interpret. If anybody's more experienced at debugging > things in the BSDs that would also be helpful. > > On OpenBSD, for comparison, each test run seems to fairly reliably > take 5 seconds give-or-take, there's much less run-to-run > variation, though it's still much slower than Linux is. > The OpenBSD and FreeBSD build VMs seem to complete more > reasonably quickly than the NetBSD one. > > One thing I noticed looking at ktrace output is that we do > all our reading of QMP input and output with a read syscall > per character. I don't think that's the cause of this slowness, > though. > > thanks > -- PMM >
I'm running these tests natively and get apparently expected results:
/x86_64/qom/pc-i440fx-2.0: OK
2,05 real 1,36 user 0,71 sys
/x86_64/qom/pc-i440fx-2.0: OK
1,92 real 1,17 user 0,79 sys
/x86_64/qom/pc-i440fx-2.0: OK
1,84 real 1,14 user 0,77 sys
/x86_64/qom/pc-i440fx-2.0: OK
1,85 real 1,16 user 0,76 sys
/x86_64/qom/pc-i440fx-2.0: OK
1,79 real 1,04 user 0,82 sys
/x86_64/qom/pc-i440fx-2.0: OK
1,84 real 1,00 user 0,91 sys
/x86_64/qom/pc-i440fx-2.0: OK
1,86 real 1,18 user 0,75 sys
/x86_64/qom/pc-i440fx-2.0: OK
1,85 real 1,27 user 0,64 sys
/x86_64/qom/pc-i440fx-2.0: OK
1,84 real 1,27 user 0,64 sys
/x86_64/qom/pc-i440fx-2.0: OK
1,82 real 1,18 user 0,71 sys
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