Hi
From a IBM AIX partner:
GIL is a kernel process, which does TCP/IP timing. It handles
transmission errors, ACKs, etc. Normally it shouldn't consume too much
CPU, but it can take quite a lot of CPU when the system is using the
network a lot (like with NFS filesystems which are heavily used).
.
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). In version 4 this work is all done on a multi-threaded kproc
to promote concurrency and SMP scalability.gil.
GIL is one of the kprocs (kernel processes) in AIX 4.3.3, 5.1 and 5.2.
Since the advent of topas in AIX 4.3.3 and changes made to the ps
command in AIX 5.1, system administrators have become aware of this
class of processes, which are not new to AIX. These kprocs have no
user interfaces and have been largely undocumented in base
documentation. Once a kproc is started, typically it stays in the
process table until the next reboot. The system resources used by any
one kproc are accounted as kernel resources, so no separate account is
kept of resources used by an individual kproc.
.
Most of these kprocs are NOT described in base AIX documentation and
the descriptions below may be the most complete that can be found.
.
GIL term is an acronym for "Generalized Interrupt Level" and was
created by the Open Software Foundation (OSF), This is the networking
daemon responsible for processing all the network interrupts, including
incoming packets, tcp timers, etc.
.
Exactly how these kprocs function and much of their expected behavior
is considered IBM proprietary information.