linux-kernel - Increased CPU usage after upgrading to 2.6.21

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Date:	Wed, 18 Jul 2007 09:43:47 -0700
From:	Gautam Iyer <gautam@...h.stanford.edu>
To:	linux-kernel@...r.kernel.org
Subject: Increased CPU usage after upgrading to 2.6.21

Hi All,

I recently upgraded from 2.6.19, and found the following issues:

    1. 2.6.20 crashed and ran terribly on my system.

    2. 2.6.21 runs on my system, but has a few issues: First, I noticed
       that in 2.6.19 when my system was idle, Gkrellm would show my CPU
       usage as 0%. In 2.6.21, when my system is idle, Gkrellm shows my
       cpu usage as anything between 1 and 3%.

       Second, I noticed that X sometimes crashes on resume (i.e. when I
       wake my computer up after suspending to ram). Again, this happens
       only *sometimes*, and is not consistently reproducible. I had no
       issues with 2.6.19 (which I used for a long time).

    3. For 2.6.22.1: The CPU usage issue is the same as above. I only
       tested the kernel for a brief period of time (minutes), during
       which I experienced no crash.

If you have any idea why my CPU usage is reported higher, please let me
know. I've attached the config files of both my kernels.

About the random crash: I'm not sure how to give you more info on it,
since I can't consistently reproduce it. Would you have any suggestions
on what I should do to trace the problem down?

Thanks in advance,

GI

PS: I'm using the kernel with Gentoo patchset. But I confirmed the above
    persists with the vanilla kernels.

PPS: I also played around with the timer frequency, and premption model.
     Would those make a difference to CPU usage?

-- 
Modern Computer Viruses:
Elvis virus -- Your computer gets fat, slow, and lazy and then self
destructs, only to resurface at shopping malls and service stations
across rural America.

View attachment ".config" of type "text/plain" (48109 bytes)

View attachment ".config" of type "text/plain" (49976 bytes)