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From Marc Slemko <ma...@znep.com>
Subject Re: roy's l_c perf patch and spareservers
Date Sat, 15 Feb 1997 03:27:37 GMT
On Fri, 14 Feb 1997, Dean Gaudet wrote:

> I put Roy's l_c perf patch on HotWired's servers for a few hours... but
> the FIN_WAIT_2s flew through the roof, so I had to go back to
> -DNO_LINGCLOSE.  (IRIX 5.3).  There was some speculation that this might
> help the FIN_WAIT_2 situation, but it doesn't look like it.  As far as
> performance goes I didn't really get a chance to compare, I'll try again.

Most important is the performance comparisons between the old
lingering_close and the one with Roy's patch, although I guess the
difference between no l_c and the new l_c tells other things that are more
important in the long-term analysis.

> 
> One idle thought I had was that we might try playing with the order of
> things -- do the shutdown(sd,1) after a select() timeout or a successful
> read(). 

Umm... I'm not sure that is nice.  The half close is the only way for the
client to know that we are terminating the connection.  If we don't do it
until later, the client won't know that the connection has been closed.
If the client doesn't know the connection is closed, it can't close its
half.  That would extend the lifetime of _all_ connections beyond what it 
is right now even with lingering_close.

> 
> The other thing I found, just like Chuck said a while back, I played with
> the Min/MaxSpareServers settings and removed all the huge spikes from my
> load averages.  The change in load *could* be related to locality of
> reference in the L2 cache, but I'm not convinced that is the only thing.
> We're talking a difference of 50% vs 20% "cpu usage" as reported by the
> status module.  (I'd really like to revamp status to do 5 minute rolling
> averages.)

Played in what way?  Just increased them both?


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