From mboxrd@z Thu Jan  1 00:00:00 1970
From: "David S. Ahern" <daahern@cisco.com>
Subject: Re: performance with guests running 2.4
 kernels	(specifically RHEL3)
Date: Wed, 14 May 2008 14:35:53 -0600
Message-ID: <482B4D29.7010202@cisco.com>
References: <48054518.3000104@cisco.com>	<4805BCF1.6040605@qumranet.com>	<4807BD53.6020304@cisco.com>	<48085485.3090205@qumranet.com>	<480C188F.3020101@cisco.com>	<480C5C39.4040300@qumranet.com>	<480E492B.3060500@cisco.com>	<480EEDA0.3080209@qumranet.com>	<480F546C.2030608@cisco.com>	<481215DE.3000302@cisco.com>	<20080428181550.GA3965@dmt>	<4816617F.3080403@cisco.com>	<4817F30C.6050308@cisco.com>	<48184228.2020701@qumranet.com>	<481876A9.1010806@cisco.com>	<48187903.2070409@qumranet.com>	<4826E744.1080107@qumranet.com>	<4826F668.6030305@qumranet.com>
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Cc: kvm-devel <kvm-devel@lists.sourceforge.net>
To: Avi Kivity <avi@qumranet.com>
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Avi Kivity wrote:
> Not so fast...  the patch updates the flood count to 5.  Can you check
> if a lower value still works?  Also, whether updating the flood count to
> 5 (without the rest of the patch) works?
> 
> Unconditionally bumping the flood count to 5 will likely cause a
> performance regression on other guests.

I put the flood count back to 3, and the RHEL3 guest performance is even
better.

> 
> While I was able to see excessive flooding, I couldn't reproduce your
> kscand problem.  Running /bin/true always returned immediately for me.

A poor attempt at finding a simplistic, minimal re-create. The use case
I am investigating has over 500 processes/threads with a base memory
consumption around 1GB. I was finding it nearly impossible to have a
generic re-create of the problem for you to use in your investigations
on CentOS.

Thanks for the patch.

david

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