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Andrew Purtell commented on HBASE-21926: ---------------------------------------- I'm going to ignore further ImportOrder checkstyle warnings, because it doesn't seem to matter where the import is placed, there is still a warning. Tired of guessing what is the right answer. As this is the only checkstyle warning the patch looks good IMHO. The javac warning is for a file untouched by this patch, StaticUserWebFilter. The whitespace warning will be fixed on commit with git am --whitespace=fix. The patch has been confirmed to work with manual testing. What else needs to be done here? I think it is ready. I need a +1 please > Profiler servlet > ---------------- > > Key: HBASE-21926 > URL: https://issues.apache.org/jira/browse/HBASE-21926 > Project: HBase > Issue Type: New Feature > Components: master, Operability, regionserver > Reporter: Andrew Purtell > Assignee: Andrew Purtell > Priority: Major > Fix For: 3.0.0, 1.5.0, 2.3.0 > > Attachments: 1.png, 2.png, 3.png, 4.png, HBASE-21926-branch-1.patch, > HBASE-21926-branch-1.patch, HBASE-21926-branch-1.patch, HBASE-21926.patch, > HBASE-21926.patch, HBASE-21926.patch > > > HIVE-20202 describes how Hive added a web endpoint for online in production > profiling based on async-profiler. The endpoint was added as a servlet to > httpserver and supports retrieval of flamegraphs compiled from the profiler > trace. Async profiler > ([https://github.com/jvm-profiling-tools/async-profiler] ) can also profile > heap allocations, lock contention, and HW performance counters in addition to > CPU. > The profiling overhead is pretty low and is safe to run in production. The > async-profiler project measured and describes CPU and memory overheads on > these issues: > [https://github.com/jvm-profiling-tools/async-profiler/issues/14] and > [https://github.com/jvm-profiling-tools/async-profiler/issues/131] > We have an httpserver based servlet stack so we can use HIVE-20202 as an > implementation template for a similar feature for HBase daemons. Ideally we > achieve these requirements: > * Retrieve flamegraph SVG generated from latest profile trace. > * Online enable and disable of profiling activity. (async-profiler does not > do instrumentation based profiling so this should not cause the code gen > related perf problems of that other approach and can be safely toggled on and > off while under production load.) > * CPU profiling. > * ALLOCATION profiling. > -- This message was sent by Atlassian JIRA (v7.6.3#76005)