· Introduction

· Supported OS

· How to use

· What's new ?

· In-depth latency tests


· Professional Edition

· Download Home Edition

· Buy Professional Edition

Technical Information

LatencyMon makes use of a kernel logger session (ETW). Because of limitations with this technology on older operating system versions, LatencyMon will only run on Windows Vista and later operating systems (including Windows 7-10 but not Windows XP).

A kernel driver is used for the purpose of obtaining virtual addresses of loaded kernel modules so that the software can resolve routine addresses to driver names. The driver also installs kernel timers which are used for general latency measuring.

The measuring of 'SMI and CPU stalls' is achieved by opportunistically reading the performance counter in a tight loop with maskable interrupts disabled.

Because LatencyMon executes DPCs as part of the process of latency measuring, certain values such as "total time spent in DPCs" reported by the software will be influenced. In order to obtain clean DPC measuring results not affected by the operation of the software, disable the following options:

  • Measure latency by means of a kernel timer
  • Measure SMI and CPU stalls
  • Perform CPU speed sanity check

    LatencyMon temporarily lowers the system clock timer resolution to 1ms in case it was previously set to a higher value.

    LatencyMon documentation and articles

     · Introduction
     · Supported Operating Systems
     · Professional Edition
     · What's new ?
     · FAQ
     · How to use LatencyMon
     · CPU Power Management issues
     · Interrupt to user process latencies
     · In Depth Latency Tests
     · SMIs and CPU stalls
     · Technical information
     · "Windows and Real-time", guest article for kernel developers published by OSR

    Note: this content is currently being updated.

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