100 Percent CPU Usage with RCMD or REMOTE (186817)

SYMPTOMS

Running the PMON Resource Kit utility under a remote command session (RCMD or REMOTE) leads to 100 percent CPU usage at the server. About 50 percent of the CPU is used by Csrss.exe and the other 50 percent by PMON. This issue may occur when using VI or many other utilities.

CAUSE

The problem is not caused by PMON and is not caused by the RCMD service but rather is a combination of the two utilities.

RESOLUTION

The recommended method of resolving this issue is to use the Remote Console resource kit utility. This utility does not redirect standard input and standard output but polls video memory changes in order to forward them to the client.

STATUS

Microsoft has confirmed this to be a problem in Microsoft Windows NT version 4.0. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

Remote Command server (RCMDSVC) only redirects standard input and output to the client so that RCMD clients are not able to see output of programs that work directly with video memory, such as EDIT, PMON and so on.

Indeed the problem can be reproduced on one hand with any remote shell solution that redirects standard input and output, and on the other hand with any tool that works with an other active screen buffer. Console applications may create several screen buffers (CreateConsoleScreenBuffer() API) and change the current active buffer (SetConsoleActiveScreenBuffer API).