Surya Hebbar has posted comments on this change. ( http://gerrit.cloudera.org:8080/22526 )
Change subject: IMPALA-13787: Compensate for inaccuracies of EC2 instances in runtime-profile-test ...................................................................... Patch Set 2: https://gerrit.cloudera.org/c/22482/3/be/src/util/runtime-profile-test.cc#2001 For the test in IMPALA-13751, it was suggested to reduce the sleep time between events to 5ms, which was less than the clock's accuracy. This was to make the test run faster. It ran successfully on machines with higher resolution clocks. But the following problem occurs on EC2 instances. https://github.com/apache/impala/blob/cfeb57c128c7f514f3433a0399966f46a49a1a4a/be/src/util/stopwatch.h#L102C1-L111C18 /// Stop watch for reporting elapsed time in nanosec based on clock_gettime (Linux) or /// MonotonicNanos (Apple). It is not affected by cpu frequency changes and it is not /// affected by user setting the system clock. A monotonic clock represents monotonic /// time since some unspecified starting point. It is good for computing elapsed time. /// /// The time values are in nanoseconds. For most machine configurations, the clock /// resolution will be 1 nanosecond. We fall back to low resolution in configurations /// where the clock is expensive. For those machine configurations (notably EC2), the /// clock resolution will be that of the system jiffy, which is between 1 and 10 /// milliseconds. Please check IMPALA-13787 for more details. -- To view, visit http://gerrit.cloudera.org:8080/22526 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I8150b7e38e7e5e5294e2dc61c16c2b102032cca2 Gerrit-Change-Number: 22526 Gerrit-PatchSet: 2 Gerrit-Owner: Surya Hebbar <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Laszlo Gaal <[email protected]> Gerrit-Reviewer: Michael Smith <[email protected]> Gerrit-Reviewer: Riza Suminto <[email protected]> Gerrit-Reviewer: Surya Hebbar <[email protected]> Gerrit-Comment-Date: Sun, 23 Feb 2025 23:06:59 +0000 Gerrit-HasComments: No
