On 19/01/2024 17.07, Daniel P. Berrangé wrote:
On Fri, Jan 19, 2024 at 03:55:49PM +0000, Thomas Huth wrote:
Hi,
since we recently introduced test timouts in QEMU's meson set up, I noticed
that the tests/unit/test-iov times out when doing "make vm-build-netbsd
BUILD_TARGET=check-unit" (or vm-build-openbsd).
And indeed, when increasing the timeout, you can see that the test-iov runs
for multiple minutes on these BSDs while it finishes within few seconds on
Linux.
I had a closer look at the test, and the problem seems to be the
usleep(g_test_rand_int_range(0, 30));
in the test_io() function. If I get that right, the usleep() seems to be
more or less precise on (modern) Linux, but it seems like it sleeps for
multiple milliseconds (not microseconds) on the BSDs. Since it is used in a
nested loop, these milliseconds add up to a long time in total during the
test.
Does anybody have an idea how to fix that? Is there a more precise (but stil
portable) way to sleep less long here? Or could we maybe remove the usleep()
here completely (it does not seem to have a real benefit for testing as far
as I can see)?
'g_usleep' has the same API contract, but is implemented in terms
of 'nanosleep' on *NIX. So as a quick test, try switching usleep
to g_usleep and see if we get lucky.
No, that seems to behave the same way, unfortunately.
Do you see a reason why we'd really need the usleep() here at all?
Otherwise, I think I'll send a patch to simply remove it...
Thomas
