I'm going nuts here. So I go to the event log viewer for system and find the Power-Troubleshooter, and this is where it gets wierd and what my main question right now is about. Here is what i get in the General tab: T he system has resumed from sleep. The times above haven't even come to pass.
How could this be? Thank you Tony. This thread is locked. You can follow the question or vote as helpful, but you cannot reply to this thread. I have the same question 6. Report abuse.
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Hypersistence Optimizer. ERP Contact. By continuing to use this website, you agree to their use. To find out more, including how to control cookies, see here: Our Cookie Policy. Therefore, as previously stated in the preceding usage guidance, only use the APIs that provide 1 microsecond or better resolution when such resolution is necessary. The TSC is used as the basis for QPC on multi-clock domain systems that include hardware synchronization of all processor clock domains, as this effectively makes them function as a single clock domain system.
The frequency of the performance counter is fixed at system boot and is consistent across all processors so you only need to query the frequency from QueryPerformanceFrequency as the application initializes, and then cache the result. The performance counter is expected to work reliably on all guest virtual machines running on correctly implemented hypervisors. However, hypervisors that comply with the hypervisor version 1. For more information about hypervisor interfaces and enlightenments, see Hypervisor Specifications.
Instead, we encourage you to use QPC to leverage the abstraction, consistency, and portability that it offers. This example shows how to use the managed code System. Stopwatch class. The System. Stopwatch class also provides several convenient methods to perform time-interval measurements. The Windows kernel provides kernel-mode access to the performance counter through KeQueryPerformanceCounter from which both the performance counter and performance frequency can be obtained.
KeQueryPerformanceCounter is available from kernel mode only and is provided for writers of device drivers and other kernel-mode components. Can it be synchronized to an external epoch such as UTC? QPC is based on a hardware counter that can't be synchronized to an external time reference, such as UTC. Is QPC affected by daylight savings time, leap seconds, time zones, or system time changes made by the administrator? Is QPC accuracy affected by processor frequency changes caused by power management or Turbo Boost technology?
If the processor doesn't have an invariant TSC, QPC will revert to a platform hardware timer that won't be affected by processor frequency changes or Turbo Boost technology. Does QPC reliably work on multi-processor systems, multi-core system, and systems with hyper-threading? How do I determine and validate that QPC works on my machine? Which processors have non-invariant TSCs?
How can I check if my system has a non-invariant TSC? You don't need to perform this check yourself. Windows operating systems perform several checks at system initialization to determine if the TSC is suitable as a basis for QPC. However, for reference purposes, you can determine whether your processor has an invariant TSC by using one of these:. An asterisk means "True". How often does QPC roll over? Not less than years from the most recent system boot, and potentially longer based on the underlying hardware timer used.
For most applications, rollover isn't a concern. What is the computational cost of calling QPC? The computational calling cost of QPC is determined primarily by the underlying hardware platform. If the TSC can't be used, the system will select a different hardware time basis. This cost is dominated by the time required to access the hardware device on the motherboard. Does QPC require a kernel transition system call? Is the performance counter monotonic non-decreasing?
Can the performance counter be used to order events in time? How accurate is the performance counter? The answer depends on a variety of factors. For more info, see Low-level hardware clock characteristics. I need to convert the QPC output to milliseconds. How can I avoid loss of precision with converting to double or float? There are several things to keep in mind when performing calculations on integer performance counters:.
As a general principle, delay these computations and conversions as long as possible to avoid compounding the errors introduced. A file time is a bit value that represents the number of nanosecond intervals that have elapsed since A. Conversion between the two requires calculating the ratio of the QPC interval and nanoseconds intervals.
Be careful to avoid losing precision because the values might be small 0. Why is the time stamp that is returned from QPC a signed integer? Calculations that involve QPC time stamps might involve subtraction. By using a signed value, you can handle calculations that might yield negative values. How can I obtain high resolution time stamps from managed code? Call the Stopwatch. GetTimeStamp method from the System.
For an example about how to use Stopwatch. GetTimeStamp , see Acquiring high resolution time stamps from managed code. Do I need to set the thread affinity to a single core to use QPC? For more info, see Guidance for acquiring time stamps. This scenario is neither necessary nor desirable. Performing this scenario might adversely affect your application's performance by restricting processing to one core or by creating a bottleneck on a single core if multiple threads set their affinity to the same core when calling QueryPerformanceCounter.
Absolute clocks provide accurate time-of-day readings. They are typically based on Coordinated Universal Time UTC and consequently their accuracy depends in part on how well they are synchronized to an external time reference. Difference clocks measure time intervals and aren't typically based on an external time epoch.
QPC is a difference clock and isn't synchronized to an external time epoch or reference.
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