Merge pull request #20432 from AspirinSJL/tune_xds

Tune xds test

test/cpp/end2end/xds_end2end_test.cc

@@ -1571,7 +1571,7 @@ TEST_F(DropTest, DropPerTenThousand) {
 TEST_F(DropTest, Update) {
   SetNextResolution({}, kDefaultServiceConfig_.c_str());
   SetNextResolutionForLbChannelAllBalancers();
-  const size_t kNumRpcs = 5000;
+  const size_t kNumRpcs = 1000;
   const uint32_t kDropPerMillionForLb = 100000;
   const uint32_t kDropPerMillionForThrottle = 200000;
   const double kDropRateForLb = kDropPerMillionForLb / 1000000.0;
@@ -1610,7 +1610,7 @@ TEST_F(DropTest, Update) {
   gpr_log(GPR_INFO, "========= DONE WITH FIRST BATCH ==========");
   // The drop rate should be roughly equal to the expectation.
   double seen_drop_rate = static_cast<double>(num_drops) / kNumRpcs;
-  const double kErrorTolerance = 0.2;
+  const double kErrorTolerance = 0.3;
   EXPECT_THAT(
       seen_drop_rate,
       ::testing::AllOf(::testing::Ge(kDropRateForLb * (1 - kErrorTolerance)),