Category Archives: xperf

32 MiB Working Sets on a 64 GiB machine

Posted on October 1, 2023 by brucedawson

Memory is a relatively scarce resource on many consumer computers, so a feature to limit how much memory a process uses seems like a good idea, and Microsoft did indeed implement such a feature. However: They didn’t document this (!) … Continue reading →

Posted in Computers and Internet, Investigative Reporting, memory, Performance, Programming, uiforetw, xperf | Tagged , , | 10 Comments

When Debug Symbols Get Large

Posted on March 8, 2023 by brucedawson

TL;DR – upgrade your tools, including Visual Studio, windbg, and Windows Performance Toolkit, if you want to handle Chromium’s symbol files. Details: Death, taxes, and browser engines relentlessly growing – those are the three things that you can really be … Continue reading →

Posted in Debugging, Programming, Symbols, uiforetw, xperf | Tagged , | 12 Comments

No Start Menu for You

Posted on January 17, 2023 by brucedawson

I tend to launch most programs on my Windows 10 laptop by typing the <Win> key, then a few letters of the program name, and then hitting enter. On my powerful laptop (SSD and 32 GB of RAM) this process … Continue reading →

Posted in Code Reliability, Debugging, Investigative Reporting, Performance, Programming, Rants, uiforetw, xperf | Tagged , , | 28 Comments

Why Modern Software is Slow–Windows Voice Recorder

Posted on September 29, 2022 by brucedawson

I apologize for this title because there are many things that can make modern software slow. Blindly applying one explanation without a bit of investigation is the software equivalent of a cargo cult. That said, this post describes one example … Continue reading →

Posted in Investigative Reporting, Performance, uiforetw, xperf | Tagged , , | 39 Comments

Windows Performance Analyzer, From Store or SDK

Posted on November 12, 2021 by brucedawson

ETW is the best way to analyze performance on Windows, and Windows Performance Analyzer (WPA) has been the preferred tool for analyzing ETW traces for ten years now, generally obtained either by running UIforETW or by getting it from the … Continue reading →

Posted in Documentation, uiforetw, xperf | Tagged , , , | 5 Comments

Finding Windows HANDLE leaks, in Chromium and others

Posted on July 25, 2021 by brucedawson

Three years ago I found a 32 GB memory leak caused by CcmExec.exe failing to close process handles. That bug is fixed, but ever since then I have had the handles column in  Windows Task Manager enabled, just in case … Continue reading →

Posted in Bugs, Code Reliability, Investigative Reporting, uiforetw, xperf | Tagged , | 20 Comments

What Outranks Thread Priority?

Posted on April 14, 2020 by brucedawson

This investigation started, as so many of mine do, with me minding my own business, not looking for trouble. In this case all I was doing was opening my laptop lid and trying to log on. The first few times … Continue reading →

Posted in Investigative Reporting, Performance, uiforetw, xperf | Tagged , , | 7 Comments

Bulk ETW Trace Analysis in C#

Posted on January 5, 2020 by brucedawson

ETW traces record a wealth of information about how a Windows system is behaving. When analyzing a new and unknown problem there is no replacement for loading the trace into WPA and following the clues to a solution. The thrill … Continue reading →

Posted in uiforetw, xperf | Tagged , | 11 Comments

O(n^2), again, now in WMI

Posted on December 8, 2019 by brucedawson

I recently hit some multi-minute delays on my workstation. After investigating I found that the problem was due to a lock being held for five minutes, and during that time the lock-holder was mostly just spinning in a nine-instruction loop. … Continue reading →

Posted in Investigative Reporting, Programming, Quadratic, Rants, uiforetw, xperf | Tagged , , , , | 23 Comments

Heap Snapshots–Tracing All Heap Allocations

Posted on October 27, 2019 by brucedawson

I’ve recently started using heap snapshots on Windows to track heap allocations. I was able to use heap snapshots to record call stacks for all outstanding allocations in Chrome’s browser process over a full two weeks, letting me account for … Continue reading →

Posted in Documentation, Performance, Programming, uiforetw, xperf | Tagged , | 23 Comments