tech-kern archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: mpt Serious performance issues



On Wed, Feb 02, 2011 at 11:29:47AM +0100, Stephan wrote:
> It seems that if one waits a while after writing some data the read
> speed isn?t that bad. I do a
> 
> find / -exec cat {} \; > /dev/null &
> 
> and monitor the read speed with "sysstat vm". It is around 60 - 70
> MB/s. This strengthens the suspicion that write caching isn?t working.

That, or the firmware does not pass reads around cached writes as it
flushes cached writes out to the disk.  This would be a pretty typical
cheap-firmware "programmer time optimization".

-- 
  Thor Lancelot Simon                                        
tls%panix.com@localhost

  "We cannot usually in social life pursue a single value or a single moral
   aim, untroubled by the need to compromise with others."      - H.L.A. Hart


Home | Main Index | Thread Index | Old Index