[PATCH v2 8/8] qtest/e1000e|igb: Test interrupt throttling in multiple_transfers test

[Nicholas Piggin <npiggin@gmail.com>]

Enable interrupt throtling on one of the two queue interrupts used
in the multiple_transfers test, to improve coverage. The number of
interrupts for the e1000e test is reduced because it has a long minimum
throttling delay so without reducing iterations throttling adds about
40s to the test runtime.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 tests/qtest/e1000e-test.c | 6 +++---
 tests/qtest/igb-test.c    | 4 ++++
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/tests/qtest/e1000e-test.c b/tests/qtest/e1000e-test.c
index a538c72cc84..645b31127f0 100644
--- a/tests/qtest/e1000e-test.c
+++ b/tests/qtest/e1000e-test.c
@@ -181,7 +181,7 @@ static void test_e1000e_rx(void *obj, void *data, QGuestAllocator * alloc)
 static void test_e1000e_multiple_transfers(void *obj, void *data,
                                            QGuestAllocator *alloc)
 {
-    static const long iterations = 4 * 1024;
+    static const long iterations = 1 * 1024;
     long i;
 
     QE1000E_PCI *e1000e = obj;
@@ -194,8 +194,8 @@ static void test_e1000e_multiple_transfers(void *obj, void *data,
         return;
     }
 
-    /* Clear EITR because buggy QEMU throttle timer causes superfluous irqs */
-    e1000e_macreg_write(d, E1000_EITR + E1000E_RX0_MSG_ID * 4, 0);
+    /* Use EITR for one irq and disable it for the other, for testing */
+    e1000e_macreg_write(d, E1000_EITR + E1000E_RX0_MSG_ID * 4, 500);
     e1000e_macreg_write(d, E1000_EITR + E1000E_TX0_MSG_ID * 4, 0);
 
     for (i = 0; i < iterations; i++) {
diff --git a/tests/qtest/igb-test.c b/tests/qtest/igb-test.c
index 12cdd8b498a..c1877a77be4 100644
--- a/tests/qtest/igb-test.c
+++ b/tests/qtest/igb-test.c
@@ -198,6 +198,10 @@ static void test_igb_multiple_transfers(void *obj, void *data,
         return;
     }
 
+    /* Use EITR for one irq and disable it for the other, for testing */
+    e1000e_macreg_write(d, E1000_EITR(E1000E_RX0_MSG_ID), 0);
+    e1000e_macreg_write(d, E1000_EITR(E1000E_TX0_MSG_ID), 10 << 2); /* 10us */
+
     for (i = 0; i < iterations; i++) {
         igb_send_verify(d, data, alloc);
         igb_receive_verify(d, data, alloc);
-- 
2.47.1