Package org.apache.hadoop.http

Class ProfileServlet

java.lang.Object

javax.servlet.GenericServlet

javax.servlet.http.HttpServlet

org.apache.hadoop.http.ProfileServlet

All Implemented Interfaces:

java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig

@Private
public class ProfileServlet
extends javax.servlet.http.HttpServlet

Servlet that runs async-profiler as web-endpoint.

Following options from async-profiler can be specified as query paramater. // -e event profiling event: cpu|alloc|lock|cache-misses etc. // -d duration run profiling for 'duration' seconds (integer) // -i interval sampling interval in nanoseconds (long) // -j jstackdepth maximum Java stack depth (integer) // -b bufsize frame buffer size (long) // -t profile different threads separately // -s simple class names instead of FQN // -o fmt[,fmt...] output format: summary|traces|flat|collapsed|svg|tree|jfr|html // --width px SVG width pixels (integer) // --height px SVG frame height pixels (integer) // --minwidth px skip frames smaller than px (double) // --reverse generate stack-reversed FlameGraph / Call tree

Example: If Namenode http address is localhost:9870, and ResourceManager http address is localhost:8088, ProfileServlet running with async-profiler setup can be accessed with http://localhost:9870/prof and http://localhost:8088/prof for Namenode and ResourceManager processes respectively. Deep dive into some params: - To collect 10 second CPU profile of current process i.e. Namenode (returns FlameGraph svg) curl "http://localhost:9870/prof" - To collect 10 second CPU profile of pid 12345 (returns FlameGraph svg) curl "http://localhost:9870/prof?pid=12345" (For instance, provide pid of Datanode) - To collect 30 second CPU profile of pid 12345 (returns FlameGraph svg) curl "http://localhost:9870/prof?pid=12345&duration=30" - To collect 1 minute CPU profile of current process and output in tree format (html) curl "http://localhost:9870/prof?output=tree&duration=60" - To collect 10 second heap allocation profile of current process (returns FlameGraph svg) curl "http://localhost:9870/prof?event=alloc" - To collect lock contention profile of current process (returns FlameGraph svg) curl "http://localhost:9870/prof?event=lock"

Following event types are supported (default is 'cpu') (NOTE: not all OS'es support all events) // Perf events: // cpu // page-faults // context-switches // cycles // instructions // cache-references // cache-misses // branches // branch-misses // bus-cycles // L1-dcache-load-misses // LLC-load-misses // dTLB-load-misses // mem:breakpoint // trace:tracepoint // Java events: // alloc // lock

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
ProfileServlet()

Method Summary

Modifier and Type	Method	Description
protected void	doGet(javax.servlet.http.HttpServletRequest req, javax.servlet.http.HttpServletResponse resp)

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doHead, doOptions, doPost, doPut, doTrace, getLastModified, service, service

Methods inherited from class javax.servlet.GenericServlet

destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, init, log, log

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ProfileServlet

public ProfileServlet()

Method Detail

doGet

protected void doGet(javax.servlet.http.HttpServletRequest req,
                     javax.servlet.http.HttpServletResponse resp)
              throws java.io.IOException

Overrides:

doGet in class javax.servlet.http.HttpServlet

Throws:

java.io.IOException