high interrupts by network interfaces

[kamal kc]

dear everybody,

i modified the bridge.c file and added a routine to
compress/decompress 
ip packet. i put my code in bdg_forward(). And ran the
pc in bridge mode.

The modified kernel is deployed in network where the
datarate is 
about 4 to 6 Mbps. One thing to be noted is that the
pc receives 
continues data at 4 to 6 Mbps rather than sudden burst
at intervals.

Now the problem is, I am getting very high interrupts
from the network 
interfaces. the cpu utilization by the interrupts is
high due to which there
is latency added to the packets forwarded by the pc.
The pc attempts to 
compress/decompress all tcp packets.

BELOW is some helpful information about the pc and top

output.

pc spec
---------
CPU: Intel(R) Pentium(R) 4 CPU 2.66GHz (2666.78-MHz
686-class CPU)
real memory  = 796131328 (759 MB)

top output:
-------------
last pid: 58610; 	 load averages:  0.06,  0.17,  0.13 
        up 16+02:58:40  16:23:31
83 processes:  	4 running, 	49 sleeping, 	30 waiting
CPU states:  0.0% user,  0.0% nice,  0.2% system,
46.5% interrupt, 53.3% idle
Mem: 7988K 	Active, 338M Inact, 	117M Wired, 	85M Buf,
	275M Free
Swap: 2048M Total, 	   2048M Free

  PID USERNAME  PRI 	NICE   SIZE    RES STATE    TIME 
  WCPU     CPU      COMMAND
   11 root   	    171  	 52      0K        8K 	RUN   
304.5H 52.54% 52.54%  idle
   31 root		   -68   	-187    0K        8K 	RUN   
44.1H   25.59% 25.59%  irq21: rl0
   32 root     	   -68  	-187    0K        8K	 WAIT  
34.9H   18.95% 18.95%  irq22: rl1
   50 root              20    	0         0K        8K 
syncer 28:01   0.00%  0.00%    syncer
   35 root		    -28  	-147    0K        8K	 WAIT   
7:50   0.00%  0.00%     swi5: clock sio

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

I could not guess why i am getting high cpu
utilization by the interrupts.

What could i do in order to reduce the cpu utilization
by the interrupt
requests because due to high interrupts the system
performance is 
very poor and almost impractical to use in real high
speed networks.

any suggestions will be highly appreciated,

thanks,
kamal






__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com