Wireless Adaptor causing DPCs to spike CPU

mks2005

mks2005

mks2005

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Joined
27 May 2004
Posts
2,400
Location
UK
Hi,

I originally posted this issue in the Windows forum but it's developed somewhat and is now almost certainly related to my network card.

The symptoms: at random I will enter a spike period. A soon as this spike period begins my wireless adaptor drops out also. One of my cores spikes to 100% use, this kills my computer and it completely hangs for about 2 seconds. It's then a matter of a couple of seconds until the next spike, and so on. This will continue until I reboot - or more recently I discovered if I disable the wireless adaptor they cease!

Using processor explorer I was able to trace the cause of the spikes. This turned out to be Deferred Procedure Calls. I don't claim to understand what they are, but I used RATTV3 to monitor my DFC to try and determine what was causing the problem.

Here's what I believe to be the key part of the log file:


Code: 
Cumulative Histogram for:      NDIS.sys  (NDIS.sys)
  #,                  Range, Label,       ISR Count,  DPC Count,  DPCTmr Count
  0,    0.00us to    0.99us, <1.00us,             0,      96371,         46773
  1,    1.00us to    1.99us, <2.00us,         18641,      62289,         73064
  2,    2.00us to    2.99us, <3.00us,       4820051,     370870,         69360
  3,    3.00us to    3.99us, <4.00us,       1536593,     782946,         40438
  4,    4.00us to    4.99us, <5.00us,        813596,    4065035,         10038
  5,    5.00us to    5.99us, <6.00us,         70070,     411226,          4135
  6,    6.00us to    6.99us, <7.00us,         12769,     291228,          1025
  7,    7.00us to    7.99us, <8.00us,          4049,     319564,          1397
  8,    8.00us to    8.99us, <9.00us,          2164,     149682,          1633
  9,    9.00us to    9.99us, <10.00us,          809,      65472,          2653
 10,   10.00us to   19.99us, <20.00us,          535,     574464,         20304
 11,   20.00us to   29.99us, <30.00us,            2,     130055,             8
 12,   30.00us to   39.99us, <40.00us,            0,      87345,           125
 13,   40.00us to   49.99us, <50.00us,            1,      48237,           980
 14,   50.00us to   59.99us, <60.00us,            1,      57121,            35
 15,   60.00us to   69.99us, <70.00us,            0,      43291,             2
 16,   70.00us to   79.99us, <80.00us,            0,      35595,             4
 17,   80.00us to   89.99us, <90.00us,            0,      25973,             0
 18,   90.00us to   99.99us, <100.00us,           0,      23418,             0
 19,  100.00us to  109.99us, <110.00us,           0,      32152,             0
 20,  110.00us to  119.99us, <120.00us,           0,      22362,             0
 21,  120.00us to  129.99us, <130.00us,           0,      15856,             0
 22,  130.00us to  139.99us, <140.00us,           0,      12421,             0
 23,  140.00us to  149.99us, <150.00us,           0,      11721,             0
 24,  150.00us to  159.99us, <160.00us,           0,      10490,             0
 25,  160.00us to  169.99us, <170.00us,           0,      12437,             0
 26,  170.00us to  179.99us, <180.00us,           0,      14880,             0
 27,  180.00us to  189.99us, <190.00us,           0,      18776,             0
 28,  190.00us to  199.99us, <200.00us,           0,      16737,             0
 29,  200.00us to  209.99us, <210.00us,           0,      15229,             0
.......
 66,  570.00us to  579.99us, <580.00us,           0,          1,             0
 68,  590.00us to  599.99us, <600.00us,           0,          3,             0
 71,  620.00us to  629.99us, <630.00us,           0,          1,             0
 73,  640.00us to  649.99us, <650.00us,           0,          1,             0
 74,  650.00us to  659.99us, <660.00us,           0,          1,             0
 81,  720.00us to  729.99us, <730.00us,           0,          1,             0
 83,  740.00us to  749.99us, <750.00us,           0,          1,             0
 89,  800.00us to  809.99us, <810.00us,           0,          1,             0
 90,  810.00us to  819.99us, <820.00us,           0,          1,             0
 96,  870.00us to  879.99us, <880.00us,           0,          1,             0
[b]1009,   10.00ms to   19.99ms, <20.00ms,            0,        592,             2
1010,   20.00ms to   29.99ms, <30.00ms,            0,          4,             0[/b]
1108, 1000.00ms and greater,  >=1000.0ms,          0,          0,           263
                              TOTALS,       7279281,    7867531,        272239


The times in bold stuck me as abnormally high in comparison to the others. NDIS.sys is network related is it not?

My network adaptor is a F5D7000UK. Since my PC upgrade I have experienced problems with connection drops outs too - requiring a connection repair until I could re-connect. I have tried different drivers including RaLink chipset generic drivers. This is a fresh OS install. On my previous system the card worked faultlessly. What has changed since the last time I used is new hardware in my system. Could this be some sort of device conflict? Could it be a problem with NDIS.sys? Could I have damaged my card?

I'm unsure as to what steps to take next really... and whether what I've assumed so far is correct. Therefore if anyone can shed some light on this I'd greatly appreciate it. Cheers.
 
Last edited:
Sorry to jack your thread. But I think I have the same problem, every minute I get some sort of interference, and its VERY annoying when Im listening to music or watching movies.
So therefore I am forced to unplugged my USB wireless adapter... when playing media...
 
I think it's related to lack of wirelsss connectivity - an unstable connection (probably caused by a dodgy router).

I've tried different wireless adaptors now, but I still get the same problem. Differen't PCI slots, different drivers, it still happens.

My other issue (which is most likely connected) is that my wireless signal has, recently, for some reason, become much weaker. This is seemingly inexplicable to me. I can't think of any changes I've made that would cause this.

Incidentally, when the CPU spikes occur, I can confirm that the signal on the wireless router exhibits a similar "spiking" effect - going from high to low, to zero, rapidly.

The only time I didn't experience the problem was with a USB adaptor, although I had even more problems with connectivity with the USB. It might have been that I was unable to use it for long enough to actually determine if the DPC problem will occur.


I was trying all last night to get a decent signal - the wireless kept dropping out. I was rotating my PC, changing the aerial angle but I still couldnt find something that wouldn't cut out after about a minute. Now this morning, I return to my PC, wireless is going off-on, off-on, I rotate the computer so the aerials facing downstairs to the router and immediately now I have a stable connection. I don't understand why I can get one now and not last night. :(
 
Ok, I think I know why "mine" is doing it...
My room mate in the bedroom below me is using something thats interfering with my USB wireless adapter... for example his Amplified Indoor Loop TV Aerial. Im pretty sure its that. Because when he is out of the house, theres no problem.
My signal strength is 100% btw. But sometimes jumps down to 30% for some reason.... Oh well.
Hope you get yours sorted.
 
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