[jira] [Comment Edited] (TEZ-4067) Tez Speculation decision is calculated on each update by the dispatcher
[ https://issues.apache.org/jira/browse/TEZ-4067?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16975416#comment-16975416 ] Ahmed Hussein edited comment on TEZ-4067 at 11/15/19 9:34 PM: -- Thanks Jon! Sure, I will change that and create a new patch. was (Author: ahussein): Thanks Jon!Sure, I will change that and create a new patch. > Tez Speculation decision is calculated on each update by the dispatcher > --- > > Key: TEZ-4067 > URL: https://issues.apache.org/jira/browse/TEZ-4067 > Project: Apache Tez > Issue Type: Improvement >Reporter: Ahmed Hussein >Assignee: Ahmed Hussein >Priority: Minor > Attachments: TEZ-4067.001.patch, TEZ-4067.002.patch, > TEZ-4067.003.patch, TEZ-4067.004.patch > > > LegacySpeculator is an object field in VertexImpl. Therefore, all events are > handled synchronously by the caller (dispatcher). This implies the following: > # the dispatcher spends long time executing updateStatus as it needs to > check the runtime estimation of the tezAttempts within the vertex. > # the speculator is per stage: lunching a speculation may not the optimum > decision. Ideally, based on resources, speculated tasks should be the ones > with slowest progress. > # the time between speculation is skewed because there is a big delay for > the dispatcher to complete a full cycle. Also, speculation will be more > aggressive compared to MR because MR waits for > "soonest.retry.after.speculate" whenever a task is speculated. On the other > hand, Tez speculates more tasks as it processes stages in parallel. > -- This message was sent by Atlassian Jira (v8.3.4#803005)
[jira] [Comment Edited] (TEZ-4067) Tez Speculation decision is calculated on each update by the dispatcher
[ https://issues.apache.org/jira/browse/TEZ-4067?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=16969556#comment-16969556 ] Ahmed Hussein edited comment on TEZ-4067 at 11/7/19 9:07 PM: - Uploaded a new patch to fix error reported in checkstyle and findbugs. was (Author: ahussein): Uploaded a new patch to fix error reported in checkstyle and windbags. > Tez Speculation decision is calculated on each update by the dispatcher > --- > > Key: TEZ-4067 > URL: https://issues.apache.org/jira/browse/TEZ-4067 > Project: Apache Tez > Issue Type: Improvement >Reporter: Ahmed Hussein >Assignee: Ahmed Hussein >Priority: Minor > Attachments: TEZ-4067.001.patch, TEZ-4067.002.patch, > TEZ-4067.003.patch > > > LegacySpeculator is an object field in VertexImpl. Therefore, all events are > handled synchronously by the caller (dispatcher). This implies the following: > # the dispatcher spends long time executing updateStatus as it needs to > check the runtime estimation of the tezAttempts within the vertex. > # the speculator is per stage: lunching a speculation may not the optimum > decision. Ideally, based on resources, speculated tasks should be the ones > with slowest progress. > # the time between speculation is skewed because there is a big delay for > the dispatcher to complete a full cycle. Also, speculation will be more > aggressive compared to MR because MR waits for > "soonest.retry.after.speculate" whenever a task is speculated. On the other > hand, Tez speculates more tasks as it processes stages in parallel. > -- This message was sent by Atlassian Jira (v8.3.4#803005)
