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Nicolas Liochon commented on HBASE-11492: ----------------------------------------- -1 patch. The patch command could not apply the patch. This works locally. Something has changed on the build process? > The servers do not honnor the tcpNoDelay option > ----------------------------------------------- > > Key: HBASE-11492 > URL: https://issues.apache.org/jira/browse/HBASE-11492 > Project: HBase > Issue Type: Bug > Components: regionserver > Affects Versions: 0.92.2, 0.98.0, 0.96.0, 0.99.0, 0.94.20 > Reporter: Nicolas Liochon > Assignee: Nicolas Liochon > Priority: Critical > Fix For: 0.99.0, 0.98.5 > > Attachments: 11492.v1.patch > > > There is an option to set tcpNoDelay, defaulted to true, but the socket > channel is actually not changed. As a consequence, the server works with > nagle enabled. This leads to very degraded behavior when a single connection > is shared between threads. We enter into conflicts with nagle and tcp delayed > ack. > Here is an example of performance with the PE tool plus HBASE-11491: > {noformat} > oneCon #client sleep exeTime (seconds) > avg latency, sleep excluded (microseconds) > true 1 0 31 > 310 > false 1 0 31 > 310 > true 2 0 50 > 500 > false 2 0 31 > 310 > true 2 5 488 (including 200s sleeping) > 2880 > false 2 5 246 (including 200s sleeping) > 460 > {noformat} > The latency is divided by 5 when the connection is shared. This is the > delayed ack kicking in. This can be fixed by really using tcp no delay. -- This message was sent by Atlassian JIRA (v6.2#6252)