Gary, As you proved, not all performance problems can be identified by performance monitoring tools. In this case, "performance" is not a good word. "Locking" may be better. We recently had a problem with TrendMicro on our RHEL 5 box. cp a 1GB file took 35 minutes for the prompt to come back, even though the copied file started to have the same checksum and size after about 1 minute. /proc/<cp pid>/status shows disk sleep state. The cp command is not killable, indicating it's in kernel mode not coming back up. strace or pstack the process hangs (but strace or pstack is killable). The message in /var/log/messages sheds light on the problem: Sep 26 11:02:11 ourhostname kernel: INFO: task cp:10658 blocked for more than 120 seconds. Sep 26 11:02:11 ourhostname kernel: "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ... Sep 26 11:02:11 ourhostname kernel: Call Trace: Sep 26 11:02:11 ourhostname kernel: [<ffffffff884a45a8>] :splxmod:closeHook+0x784/0x9d8 So some splxmod module's closeHook function is the suspect since it's at the top of the call stack. Searching on Google indicates it's a module in TrendMicro's software. We contacted them and they quickly provided a patch. RHEL 4 doesn't have /proc/sys/kernel/hung_task_timeout_secs. I'm not sure if the kernel can be reconfigured to add that. For those interested, the source code is at http://koders.com/c/fidFAF17DCD13DB287057ACC4136EEEFE2D9644BA9A.aspx In your case, can you try pstack and strace on a simple process such as date (both programs need to be installed)? And tell us /proc/<pid>/status. Yong Huang -- redhat-list mailing list unsubscribe mailto:redhat-list-request@xxxxxxxxxx?subject=unsubscribe https://www.redhat.com/mailman/listinfo/redhat-list
