Trying again without the verboten 80kB PNG attachment...
On 04/12/2011 3:18 PM, Ryan Johnson wrote:
On 04/12/2011 2:29 PM, Christopher Faylor wrote:
On Sun, Dec 04, 2011 at 02:55:13AM -0500, Ryan Johnson wrote:
On 25/11/2011 10:47 AM, Spiro Trikaliotis wrote:
Hello,
* On Thu, Nov 24, 2011 at 07:59:58PM -0500 Ryan Johnson wrote:
Lately I've noticed that running make -j4 on my quad-core win7-x64
machine causes it to become sluggish or even unresponsive.
I have seen very similar effects on my Win7-64 box. I can force the
problem here just be running "ccrypt", though, I do not need to use
"make
-j4".
I assume it has to do with the Windows 64 bit problems of Cygwin
(search
the ML archives for that).
For me, this is the first machine since years where I do not use
Cygwin
because of this issue.
Update: I hit the problem again, this time running python, and the
problem is repeatable with the native 64-bit windows python
interpreter.
It looks like cygwin doesn't cause the problem, but rather my high-cpu
tasks tend to run under cygwin. Honestly, I wouldn't expect cygwin
to be
the cause, given that it's a user space only piece of software!
Now what other entity could be the cause, I haven't a clue... process
explorer doesn't show anything. Maybe that's because it's frozen along
with the rest of the world during these episodes; right as it comes
back
I see context switch deltas above 100k for the interrupt/DPC module,
which suggests I've got a wonky driver somewhere.
Out of curiousity, is the current snapshot any better? I just found a
case where Cygwin could essentially enter a tight loop while waiting for
I/O. It would seem to be working correctly but it would use a lot of
CPU time.
Again, I'm no longer convinced that this is Cygwin's fault -- it just
so happened that all my CPU-intensive tasks were cygwin apps. I'm
starting to notice a pattern, though: with three cpu-bound apps
running, my laptop's fan comes on every two minutes (precisely). About
five seconds later, the frequency drops by 50% and cpu util promptly
saturates as a result. After one minute of this, the frequency hikes
back up and we're good... until the cycle repeats a minute later (see
the attached snippet of screen shot).
So, the questions are how come:
- power/heat management isn't giving the fan a chance to work before
clamping the clock frequency?
- scheduler can't cope better with 100% cpu util?
While I'm glad to take any expert advice people might have, I think we
can close this thread as far as Cygwin is concerned.
BTW, Corinna's advice to disable PCA did help somewhat (and
Firefox/Thunderbird util dropped as well as a bonus). However, it's
probably only a treatment of symptoms in my case; I already had
superfetch disabled.
Thanks,
Ryan
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