ITEM: CG7981L

RISCO: What is the kproc gil?

WWQ&A Question: 

We have identified a kproc named gil that is using a high amount of
cpu on a wide node in our SP system.  We are at AIX 4.1.4.  Can you
tell us what gil is, and under what circumstances it might consume a
high amount of cpu?  Thank you

Response:

The kproc gil runs the TCP/IP timer driven operations.
Every 200ms, and every 500ms the GIL thread is kicked to go run protocol
timers.  With TCP up (which is ALWAYS the case), TCP timers are called
which end up looking at every connection on the system (to do
retransmission, delayed acks,etc). This wasn't seen on 3.2 because this
work was done on the offlevel interrupt and thus was not a runnable
process. In version 4 this work is all done on a multi-threaded kproc
to promote concurrency and SMP scalability.

Basically the output for gil is incorrect. For example load average
might give you 1.01 instead of 0.01 that you might expect.

We would suggest ordering ix52496 to fix the problem.




Support Line: RISCO: What is the kproc gil? ITEM: CG7981L

Dated: October 1996 Category: N/A

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