Messages in this thread | | | Date | Wed, 29 Sep 2010 09:29:24 +0200 | From | Florian Mickler <> | Subject | Re: Linux 2.6.35.6 |
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On Tue, 28 Sep 2010 15:03:58 -0400 tmhikaru@gmail.com wrote:
> On Tue, Sep 28, 2010 at 08:35:05AM +0200, Florian Mickler wrote: > > > > > > Here's a graphical example of just how wacky this is: > > > > > > http://yfrog.com/6lloadbp > > > > > > In this image, the dip down to less than 0.5 after the 18'th is due to me > > > experimenting using the slackware distribution kernel (2.6.33.4) after I > > > finally noticed something was amiss. The sharp rise afterwards is due to me > > > first, building 2.6.35.5, and then afterwards, using it. To be perfectly > > > clear, I've previously used 2.6.34.2 and did not experience the problem > > > there either, nor is it in 2.6.33.4. > > > > What load figure are you basing your observations on? The 15 minutes > > average should be the most interesting (sampled at a 7 minutes > > interval...) > > my observations are based on letting the machine idle immediately after > bootup. I monitor the state of the machine using a program called conky, > which I have configured to show disk I/O, cpu use, swap I/O and among other > things, the load average. Immediately after booting my loadaverage tends to > peak at about 2.5 to 3.0; on a working kernel this eventually settles down > to 0.00 to 0.05 in about ten minutes. On kernels that exhibit this problem, > it doesn't settle lower than 0.3 and is much more likely to hang anywhere > from 0.8 to 1.2. In fact, if I give it enough time it'll raise and lower > itself constantly without any (visible) work being done. So basically I boot > the machine and go get a drink, come back, and if it's been ten minutes, > there's been no disk IO, cpu use, or any other activity recorded and it's > still above 0.3 something's not working right.
Do you know what load average conky is showing you? If I type 'uptime' on a console, i get three load numbers: 1minute-, 5minutes- and 15minutes-average. If there is a systematic bias it should be visible on the 15minutes-average. If there are only bursts of 'load' it should be visible on the 1 minutes average numbers.
But it doesn't really matter for now what kind of load disturbance you are seeing, because you actually have a better way to distinguish a good kernel from a bad:
On Mon, 27 Sep 2010 12:32:08 -0400 tmhikaru@gmail.com wrote:
> *Something* is wrong beyond the > mere loadaverage numbers going crazy however, since timed runs of kernel > compiles done with my distro's kernel and 2.6.35.5 show that while there is > no *apparent* use of cpu or disk showing in vmstat while the machine is > idle, the compiles on the newer kernel are taking approximately twice as > long as before.
> If you're talking about the graph, > I merely posted it to show that I've been having this problem for over a > month, and it's demonstrably causing very inconsistent load averages. (Which > is why the graph isn't anything close to a line, it's a mess!) the graph > takes a reading every five minutes, if you were wondering about the sample > rate.
Yes, the sample rate was one of the things I wanted to know, but also which of the 3 load figures you were graphing.
> In other news, I'm in the process of bisection but keep having to skip > bisects that have compile errors. sigh. still at 12 hops, somewhere around > five thousands commits to check.
Good.
> > Tim McGrath >
Regards, Flo
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