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The following changes were made to LatencyMon 4.00 since version 3.00

CPU view

LatencyMon is now equipped with a CPU view which shows the interrupts and DPCs per CPU.

Processor group aware

LatencyMon is now processor group aware. It properly reports the amount of processors in the system in case multiple active processor groups exist. The per CPU view will display group and number information of each processor in the system.

Interrupt cycle times

LatencyMon now reports ISR and DPC cycle times per CPU obtained from the operating system. This feature is only available on Windows 7 and higher.

Export option from all views

You can now export the contents of views to a text file by selecting the Export option from the main menu.

Configurable buffer sizes and ETW options

A page with options has been added which allow you to configure the buffer size that is used internally by ETW as well as the minimum and maximum buffers and ETW file size that the software makes use of. A smaller ETW file size will help you to reduce CPU consumption of LatencyMon but means you may miss out on certain events.

Status bar displaying time running

A status bar has been added which displays the time LatencyMon has been active so that this information is available regardless of the view that is currently selected.

Several small bug fixes and changes

Several small bugs and unspecified problems have been fixed in this latest version.

The following changes were made to LatencyMon 3.00 since version 2.05

License update

LatencyMon now comes in two editions: a home edition and a professional edition. The home edition will be available for free but is licensed for use at home only.

Now measures kernel timer latency

While previous version of LatencyMon would only report execution times of DPCs and ISRs, the software is now equipped to actually measure latencies by means of a kernel timer. This feature is optional and can be switched off.

Now measures SMIs and 'mysterious' CPU stalls

LatencyMon now measures 'unexplainable' CPU stalls which are not caused by the operating system or any drivers. These latencies may be caused by SMIs (System Management Interrupts), CPU bugs or other CPU factors. This feature is optional and can be switched off.

Bug fixed: main application window would sometimes not show up

A bug has been fixed which prevented the software from displaying its main application window in rare cases.

Monitor feature removed

The functionality which displayed individual ISR and DPC routines in real-time has been removed. The reason for this is that the software could never keep up with the amount of events generated.

Now displays total time spent in ISRs and DPCs

LatencyMon now displays total time spent in ISRs and DPCs as well as time spent in drivers with the highest CPU consumption. Because multiple ISRs and DPCs may be executing consecutively, this information may help find the root cause of stalls in certain cases.

Feature added to stop reporting if obtained results become inaccurate

LatencyMon now stops reporting in case it cannot keep up with the amount of information it receives.

More details and per CPU information

LatencyMon now displays more detailed information in the stats view, including system information and ISR and DPC excecution times per CPU.

Lower CPU consumption

LatencyMon has been redesigned to reduce CPU consumption. This is important because previous versions could influence the behavior of the system and thus obfuscate certain latency problems related to CPU power management.

The following changes were made to LatencyMon 2.05 since version 2.04

Installer warning added

The installer will display a warning message if an attempt is made to install LatencyMon on an operating system version prior to Windows Vista.

By default, no driver and process information is obtained at startup.

By default, no driver and process information is obtained at startup. Some users had problems running LatencyMon because an antivirus or other security product would block its operations at startup. Now by default, the interface is shown and no driver and process information is displayed until the start button is clicked. This behavior can be changed in the options dialog.

CPU Speed Sanity Check

LatencyMon optionally does a rough attempt of measuring your actual CPU frequency as a sanity check. If the measured speed is only a fraction of the reported speed, a warning is added to the report text to check your actual CPU frequency and temperature.

The following changes were made to LatencyMon 2.04 since version 2.03

Minifilter altitude changed

The minifilter component that LatencyMon makes use of was installed at an altitude that was conflicting with other products. We have updated the altitude to the level that has been recently assigned to us by Microsoft.

The following changes were made to LatencyMon 2.03 since version 2.02.

LatencyMon could stop unexpectedly after running for some time

LatencyMon could stop gathering data unexpectedly after running for some time, so it would look as if the program was hanging. This was due to a bug which has been fixed.

The following changes were made in LatencyMon 2.02 since version 2.01.

Memory consumption problem solved

LatencyMon would grow its memory consumption over time causing the software to become unusable for monitoring over extended periods of time and defeating its purpose as an objective hard pagefault monitor. This problem has been fixed.

The following changes were made in LatencyMon 2.01 since version 2.00.

Sorting on columns with numeric values problem solved

Certain data columns with numeric values were not always properly sorted but sorted alphabetically instead in case the column header was clicked. This problem has been fixed.

The following changes were made in LatencyMon 2.00 since version 1.00.

Monitor disabled by default

The monitor has been disabled by default. The reason for this is that because of the large amount of events per seconds it collected (in particular ISRs) it defeats its purpose as a useful tool for measuring hard pagefaults. Just leaving it running for a few seconds would already guarantee a heavy memory load. The monitor can still be switched on but hard pagefault measurings will be influenced.

Advanced monitoring options

You can set a minimum execution time for ISRs and DPCs or switch event collection off completely. This way you can avoid collecting large volumes of data which influences accuracy of the measuring of hard pagefaults.

Now displays hard pagefaults per process

LatencyMon now displays the hard pagefault count per process. This prevents the need of using the monitor to find out what processes were hit by hard pagefaults.

Now displays ISR count, DPC count and highest execution time per driver

The driver view now displays ISR count, DPC count and highest execution times per driver. By sorting on the highest execution time column you can see all drivers which are causing latency problems.

Clipboard text and screenshot functions

Clipboard functions have been added under an Edit menu. You can copy all report text or save a screen shot to the clipboard.

CPU options moved to Options menu

CPU options (previously located at the left of the screen) have been moved to the Options menu.

Bug solved finding process for pagefault

Previous versions had often problems finding the process in which pagefaults occurred. This has been fixed.

Check for updates

You can now check if a later version of LatencyMon exists from the Help menu.