Michael Ho has posted comments on this change. ( http://gerrit.cloudera.org:8080/9158 )
Change subject: IMPALA-6449: Use CLOCK_MONOTONIC in ConditionVariable ...................................................................... Patch Set 1: (1 comment) http://gerrit.cloudera.org:8080/#/c/9158/1/be/src/util/condition-variable.h File be/src/util/condition-variable.h: http://gerrit.cloudera.org:8080/#/c/9158/1/be/src/util/condition-variable.h@39 PS1, Line 39: pthread_condattr_setclock(&attrs, CLOCK_MONOTONIC); > CLOCK_MONOTONIC can be very slow on EC2: IMPALA-2407 CLOCK_MONOTONIC_COARSE may be a bit too coarse for our purpose here given some callers of ConditionVariable do pass in micro-seconds duration. My understanding from internet sources (https://blog.packagecloud.io/eng/2017/03/08/system-calls-are-much-slower-on-ec2/) about this slowness is that gettimeofday() (which boost::get_system_time() will call) is in the same ballpark as clock_gettime(CLOCK_MONOTONIC, ...) so it's not exactly regressing. -- To view, visit http://gerrit.cloudera.org:8080/9158 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I81611cfd5e7c5347203fe7fa6b0f615602257f87 Gerrit-Change-Number: 9158 Gerrit-PatchSet: 1 Gerrit-Owner: Michael Ho <[email protected]> Gerrit-Reviewer: Jim Apple <[email protected]> Gerrit-Reviewer: Michael Ho <[email protected]> Gerrit-Comment-Date: Wed, 31 Jan 2018 00:18:48 +0000 Gerrit-HasComments: Yes
