Some hosts are slow or overloaded so test execution takes a long time.
Test cases use timeouts to protect against an infinite loop stalling the
test forever (especially important in automated test setups).
Commit 6cd14054b6 ("libqos virtio:
Increase ISR timeout") increased the clock_step() value in an attempt to
lengthen the virtio interrupt wait timeout, but timeout failures are
still occuring on the Travis automated testing platform.
This is because clock_step() only affects the guest's virtual time.
Virtio requests can be bottlenecked on host disk I/O latency - which
cannot be improved by stepping the clock, so the fix was ineffective.
This patch changes the qvirtio_wait_queue_isr() and
qvirtio_wait_config_isr() timeout mechanism from loop iterations to
microseconds. This way the test case can specify an absolute 30 second
timeout. Number of loop iterations is not a reliable timeout mechanism
since the speed depends on many factors including host performance.
Tests should no longer timeout on overloaded Travis instances.
Cc: Marc Marí <marc.mari.barcelo@gmail.com>
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
70556264a8