Jakarta crashes after 900+ simultaneous connection

[Santosh Pasi <sp...@diskonnet.com>]

Hi everyone,

We are doing some stress testing. My problem is that when number of 
connections reaches around 940..980, jakarta crashes with following messages-------------------------------------------------------------
SIGSEGV   11*  segmentation violation
    si_signo [11]: SIGSEGV   11*  segmentation violation
    si_errno [0]: Success
    si_code [0]: SI_USER [pid: 0, uid: 0]
        stackpointer=0x4c558554

Full thread dump Classic VM (1.2.2-L, green threads):
    "ppp202" (TID:0x40fb7190, sys_thread_t:0x8d0dec0, state:R) prio=5
        at java.net.SocketInputStream.socketRead(Native Method)
        at java.net.SocketInputStream.read(SocketInputStream.java:86)
        at java.net.SocketInputStream.read(SocketInputStream.java:67)
        at java.io.InputStreamReader.fill(InputStreamReader.java:159)
        at java.io.InputStreamReader.read(InputStreamReader.java:235)
        at java.io.BufferedReader.fill(BufferedReader.java:133)
        at java.io.BufferedReader.readLine(BufferedReader.java:270)
        at java.io.BufferedReader.readLine(BufferedReader.java:325)
        at IRCClient.run(IRCClient.java:799)
    "bumba174" (TID:0x40f88f90, sys_thread_t:0x8d0b358, state:CW) prio=5
        at java.lang.Thread.sleep(Native Method)
        at IRCClient.run(IRCClient.java:765)
    "sunny1176" (TID:0x40f75b28, sys_thread_t:0x8d0b930, state:CW) prio=5
        at java.lang.Thread.sleep(Native Method)


......
......

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

We are using redhat 6.2 Linux, kernel 2.2.16, Tomcat-jakarta-3.2.1, 
apache 1.3.14.
Hope to get some reply.

Regards,
Santosh Pasi

Re: Jakarta crashes after 900+ simultaneous connection

[Dan Garcia <dg...@domania.com>]

On Fri, 10 Aug 2001, Santosh Pasi wrote:
> -------------------------------------------------------------
> We are using redhat 6.2 Linux, kernel 2.2.16, Tomcat-jakarta-3.2.1, 
> apache 1.3.14.

Most importantly, what version of the JDK are you using?  (and are you
running on an SMP system?) - there are some bizarre sigsev violations that
i've made disappear by upgrading to the latest JDK.

The other possible issue you're running into is linux typically has set
limits on the number of file descriptors (which network connections are
a type of) per process, and this number is typically around 1024... 
(and given the other file descriptors that may be open internally for
other purposes - would explain your crashings around the upper 900's)

    echo "Upping system limits"
    echo 16384 > /proc/sys/fs/file-max
    echo 65536 > /proc/sys/fs/inode-max

is what I use on our production servers.  Note - you -may- have to
make a kernel change to go to some of these higher numbers...

Cheers,

--Dg