Re: Differed Procedure Calls?
- From: Paul <nospam@xxxxxxxxxx>
- Date: Mon, 13 Apr 2009 21:05:29 -0400
Muddle wrote:
Andrew McLaren wrote:Muddle wrote:Have a laptop that I never used to have a problem viewing DVD's on. If
the external power supply is plugged in DPC's spike their CPU usage
Hi Bernie
I think that's actually "Deferred Procedure Calls" :-)
There's no simple answer to your question. DPC behaviour will be
determined by a combination of many factors: motherboard, chipset,
graphics card, whether you have a multiproc system or not, what version
of video driver is installed, and what devices are generating ISRs and
DPCs.
But, in general terms ... if the laptop used to be able to show DVDs
okay, and now you have this problem with DVDs, then we'd have to ask:
"What changed"? Did you install an updated driver? New firmware? new
codec? etc, etc.
There aren't many things you can tweak to change the DPC rate, as such.
More likely, it's a by-product of behaviour in a kernel-mode driver,
probably the video driver. So, make sure you have the latest and
greatest driver for your laptop's graphics card. Plus all the usual
"health and efficiency" steps for maintaining a machine.
How are you determining that DPCs are spiking? 3rd party tools aren't
always very reliable; Perfmon is the best tool for accurate tracking of
DPCs. It would also help to know exactly what model of laptop you are
using, what its specs are and what version of video driver is installed.
Even with that info, there might not be a clear answer; but there's more
chance than with the pretty vague problem description we have so far.
Cheers,
Andrew
Perfmon is what I'm using. It's a Sony PCG-GRZ660 with an ATI Mobility Radeon 7500, Pentium 4 2.40GHz 2.39GHz, 1.00 GB RAM. Service Pack 3 and all updates installed. It has the only updated video driver ever offered by Sony and ATI for the graphics card installed and all other applicable Sony drivers are updated. All unused hardware has been disabled, it has Soundblaster USB audio, Logitech USB mouse, Sony USB external DVD +- RW drive, USB HP scanner and printers. I've installed and rolled back drivers for everything possible. As I've said the only thing that appears to change the behavior of DPC's is to unplug the external pwer supply. If I do that DPC's behaves and the system works fine until the battery runs down. My next step would probably be to reinstall the Operating system, which I haven't done since I purchased it about seven or eight years ago.
I went looking for something, to give more info about DPCs. I tried
Process Explorer at first, just to be able to set up a test case with
some DPC activity (leave a 3D game running in the background). I started
reading about "tracelog" and "tracerpt", but the problem was, I couldn't
get my hands on a version of tracelog which supported the -dpcisr option.
(Based on info on the Microsoft site, I downloaded a 1.3GB DVD iso file
for nothing, only to find in the release notes that tracelog was not
present.) There is supposed to be one for Vista that might work, but I
cannot find it.
This program appears to give much the same information. It is a little
tricky to use, until you start looking in C:\WINDOWS\system32\LogFiles\RATTV3.
The trace data collected is stored in that folder, as is the final text
output. There is an icon in the tray to control it, and you can uninstall
it when you're finished.
http://www.microsoft.com/whdc/DevTools/tools/RATT.mspx
You would start that running, before playing the DVD. It will collect
data in 3 minute chunks, and then include the information into the report.
Maybe you could collect some data before playing the DVD first, to get
a trace with some "good" data in it, to contrast to what happens
when the DVD plays. Let it run for six minutes, so the output report
has a couple chunks of data included in the trace.
Then you can play the DVD, and leave RATT running, and again look
at the log file.
But when you look at the report, it shows a "time bucket" distribution,
of response times for various pieces of software. Whether any of those
actually indicates a problem, is what I couldn't figure out. I looked
at my output, and couldn't really make any sense out of it. Maybe
you'll get a hint by using it.
Since your processor is a Pentium 4, that eliminates something like a
missing AMD dual core CPU driver or whatever, as a root cause.
*******
Another theory you could work on, is overheating. It is possible
your processor is modern enough to support "throttling", which
is an internal response to overheating. This article demonstrates
the use of RMClock to detect throttling. Throttling might start,
if the CPU gets over 70C.
http://www.xbitlabs.com/articles/cpu/display/oc-guide_7.html
RMClock Utility 2.35
http://cpu.rightmark.org/download.shtml
If you just want to watch the CPU temperature itself, without
monitoring the throttle bit, you can use Speedfan, which
interfaces to the hardware monitor interface on the motherboard.
It probes the low speed buses on the computer, looking for
a hardware monitor (which is why the program is a little
slow to start up). Many computers have the CPU diode,
tied into the hardware monitor.
http://www.almico.com/speedfan437.exe
To verify the processor speed (which can vary due to the
use of EIST, the Enhanced Intel Speed Step), you can use
a program like CPUZ. It will update the CPU frequency at
regular intervals. When running on battery, you might
see a "low" and "high" frequency displayed in CPUZ.
The Power scheme used on battery, and on line power, is
different. When on line power, the CPU frequency can run
at full speed, depending on how the power scheme sets
things up.
http://www.cpuid.com/cpuz.php
HTH,
Paul
.
- References:
- Differed Procedure Calls?
- From: Muddle
- Re: Differed Procedure Calls?
- From: Andrew McLaren
- Re: Differed Procedure Calls?
- From: Muddle
- Differed Procedure Calls?
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