[CentOS] pdflush kernel thread pops up every 10 seconds or so and video decoding grinds to a halt for 1/2 a second

Wed Oct 20 21:50:58 UTC 2010
Lamar Owen <lowen at pari.edu>

On Monday, October 18, 2010 09:25:41 pm Aleksey Tsalolikhin wrote:
> Hi. A friend of mine was doing real-time video decoding on
> Fedora Core 13 and he had a performance glitch (1/2 a second
> freeze) every 5-10 seconds.  "top" showed flush-253:0
> process at the moment of the freeze.
> He also tried CentOS 5.5, and saw a "pdflush" process popping
> up with the same frequency, and resulting in a similar glitch.
> Any other suggestions?

What kind of hard drive is this?  How is/are your drive(s) set up?

You need the iostat program (in the sysstat package, I think) to give you more detail; there are some pointers to its use in this list's archives.