Slow System and Network, High PF usgae

Hi,

The PC: Eight CPU system with 3 GB of RAM, /3G and /USERVA=2500 in boot.ini,
few processes, each can use up to 1.5 GB of virtual memory. PF usage is above
3 GB.
The total CPU usage is about 23% but the ping response is about 50 ms or
more. The user interface response(mouse, starting processes with GUI) is not
perfect (somehow slow). This system, after running for almost a day, suddenly
experiences a 100% CPU usage and the network is very slow (ping response
average is 800 ms).

What is the cause of this low performance?
Would adding memory to the system improve this situation?


Any comment or idea is really appreciated.

Thanks,

Daniel

Daniel <> wrote:
>
>The PC: Eight CPU system with 3 GB of RAM, /3G and /USERVA=2500 in boot.ini,
>few processes, each can use up to 1.5 GB of virtual memory. PF usage is above
>3 GB.
>The total CPU usage is about 23% but the ping response is about 50 ms or
>more. The user interface response(mouse, starting processes with GUI) is not
>perfect (somehow slow). This system, after running for almost a day, suddenly
>experiences a 100% CPU usage and the network is very slow (ping response
>average is 800 ms).
>
>What is the cause of this low performance?

It's not immediately clear to me that /3G is a net win in your situation.
You're limiting the kernel address space, which includes all of the page
tables for all of those huge processes. Have you tried running without
/3G?

>Would adding memory to the system improve this situation?

Which operationg system? The non-server operating systems will not use any
memory above the 4GB mark at all. You could try Win 7 64-bit. That allows
larger virtual address spaces, even for 32-bit processes.
--
Tim Roberts,
Providenza & Boekelheide, Inc.

The OS is XP. I agree hat win 7 would be ideal solution but I am trying to
understand why the system suddenly experiences 100% Total CPU. Can the
excessive page fault causes a 100% total CPU (8 CPUs)? Is the the physical
memory the bottleneck in this situation? note that there were still non-page
pool available. I got few performance monitor counters but they were not
conclusive.
--
Thanks,

Daniel


"Tim Roberts" wrote:

> Daniel <> wrote:
> >
> >The PC: Eight CPU system with 3 GB of RAM, /3G and /USERVA=2500 in boot.ini,
> >few processes, each can use up to 1.5 GB of virtual memory. PF usage is above
> >3 GB.
> >The total CPU usage is about 23% but the ping response is about 50 ms or
> >more. The user interface response(mouse, starting processes with GUI) is not
> >perfect (somehow slow). This system, after running for almost a day, suddenly
> >experiences a 100% CPU usage and the network is very slow (ping response
> >average is 800 ms).
> >
> >What is the cause of this low performance?
>
> It's not immediately clear to me that /3G is a net win in your situation.
> You're limiting the kernel address space, which includes all of the page
> tables for all of those huge processes. Have you tried running without
> /3G?
>
> >Would adding memory to the system improve this situation?
>
> Which operationg system? The non-server operating systems will not use any
> memory above the 4GB mark at all. You could try Win 7 64-bit. That allows
> larger virtual address spaces, even for 32-bit processes.
> --
> Tim Roberts,
> Providenza & Boekelheide, Inc.
> .
>

Daniel <> wrote:
>
>The OS is XP. I agree hat win 7 would be ideal solution but I am trying to
>understand why the system suddenly experiences 100% Total CPU. Can the
>excessive page fault causes a 100% total CPU (8 CPUs)? Is the the physical
>memory the bottleneck in this situation? note that there were still non-page
>pool available. I got few performance monitor counters but they were not
>conclusive.

Did you track page faults? Running out of physical memory can easily cause
all of the CPUs to dedicate themselves to thrashing to the page file.

Non-paged pool is a pool of virtual address SPACE, not physical memory.
--
Tim Roberts,
Providenza & Boekelheide, Inc.