JDK-4187127 : java.io.DataInputStream.readUTF is slow
  • Type: Bug
  • Component: core-libs
  • Sub-Component: java.io
  • Affected Version: 1.1.7
  • Priority: P4
  • Status: Closed
  • Resolution: Duplicate
  • OS: windows_nt
  • CPU: x86
  • Submitted: 1998-11-04
  • Updated: 2013-11-01
  • Resolved: 1999-04-19
Related Reports
Duplicate :  
Relates :  
Description

Name: tb29552			Date: 11/04/98


Turtlespeed_Server.java:
The server is listening on Port 523.
When a connection is comming in, the class Connection is used to accept
the client.
The run function reads a string from the client, adds a number an
returns it to the 
client. The Server stops when it's reading #finish# .

Turtlespeed_Client.java:
The client is contacting the loopback-device on Port 523.
A connection to the Server is created and 5 strings are sent. The
returned strings are
put to the console.

-----------------------------------------------------------------------------

My configuration (NT 4.0 Sp3):
AMD K6-200
128MB Dimm
3c900 Network Interface Card
JRE 1.1.7 or Java Workshop 2.0 (incl. Service Pack)

The client needs about 5sec to get the 5 strings from the server.


My configuration (Linux 2.0.35)
Intel P200
32MB Edo
Realtek 8029 NIC
The Kernel supports java

The client needs less then 1sec !!!!

---------------------------------------------------------------------------------

I took the Profiler included in the Workshop. I found out that readUTF
needs the most time.
In my case it cumulative time is 2001ms and it is called 6 times. One
readUTF needs
333.5 msec. With the Profiler you can see that DataInputStream.readUTF
calls 
DataInputStream.readUnsignedShort. This function is wasting the time.
It is declared as native, so I can't look inside it.

My question:
Why is the Java Virtual Machine so slow? What can I do to speed up my
program?
At developer.javasoft.com if found a bug report. It's number is 4106792.
It's about 
a performance-problem also including java.net.

Best reguards,
Bernhard Boeck
MB-Computersysteme Ges.m.b.H.
Kohlstatt 19
A-4893 Zell am Moos 
Austria

(Review ID: 40394)
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Comments
WORK AROUND Name: tb29552 Date: 11/04/98 Use Linux. ======================================================================
11-06-2004