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Re: high sys time, very very slow builds on new 24-core system

On Thu, Mar 24, 2011 at 04:05:07PM +0000, Eduardo Horvath wrote:
> On Thu, 24 Mar 2011, Andrew Doran wrote:
> > I have a suspicion that SSD could cause issues for us because the buffer
> > cache and other parts of the I/O system are not designed with near
> > instantaneous request->response in mind, but that likely isn't at play
> > here.. Do you have logging turned on for the SSD?
> Do you have a pretty standard SSD or something that's write optimized?  
> While it's probably not the cause of your performace problem since you're 
> spinning in the kernel rather than idle waiting for an interrupt, SSDs are 
> usually optimized for reads.  While they have zero seek times, the write 
> cycles tend to be slow compared to spinning media.

As I said: only the sources are on SSD.  And they have been preloaded into
the page cache by tar cf - /usr/src > /dev/null before the build.

The obj, destination, and release directories are on tmpfs.
So I am hopeful this has nothing to do with the disk subsystem!

Thor Lancelot Simon                                     
    And now he couldn't remember when this passion had flown, leaving him so
  foolish and bewildered and astray: can any man?
                                                   William Styron

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