Author Archives: brucedawson

About brucedawson

I'm a programmer, working for Google, focusing on optimization and reliability. Nothing's more fun than making code run 10x as fast. Unless it's eliminating large numbers of bugs. I also unicycle. And play (ice) hockey. And sled hockey. And juggle. And worry about whether this blog should have been called randomutf-8. 2010s in review tells more: https://twitter.com/BruceDawson0xB/status/1212101533015298048

Please Restore Our Registers When You’re Done With Them

“Hey, you. Yes you, that function over there. When you’re cleaning up please remember to restore all of my registers. Yes, that one too – what do you think this is, Linux?” That’s the problem I was dealing with in … Continue reading

Posted in Chromium, Debugging, Investigative Reporting, Symbols | Tagged , , | 23 Comments

Why Modern Software is Slow–Windows Voice Recorder

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 , , | 33 Comments

Slower Memory Zeroing Through Parallelism

While investigating some performance mysteries in Chrome I discovered that Microsoft had parallelized how they zero memory, and in some cases this was making it a lot slower. This slowdown may be mitigated in Windows 11 but in the latest … Continue reading

Posted in Investigative Reporting, Performance, uiforetw | Tagged , | 11 Comments

11 mm in 1.25 nanoseconds

In 2004 I was working for Microsoft in the Xbox group, and a new console was being created. I got a copy of the detailed descriptions of the Xbox 360 CPU and I read it through multiple times and suddenly … Continue reading

Posted in Fun, Performance, Xbox 360 | Tagged , , | 10 Comments

Determinism Bugs, Part Two, Kernel32.dll

It was literally the day after I cracked the __FILE__ determinism bug that I hit a completely different build determinism issue. I was asked to investigate why the Chrome build number reported for Chrome crashes on Windows 11 was lagging … Continue reading

Posted in Bugs, Chromium, Computers and Internet, Investigative Reporting, Programming, Symbols | Tagged , , | 19 Comments

Two Deterministic Build Bugs

‘Twas the week before Christmas and I ran across a deterministic-build bug. And then another one. One was in Chromium, and the other was in Microsoft Windows. It seemed like a weird coincidence so I thought I’d write about both … Continue reading

Posted in Bugs, Chromium, Computers and Internet, Debugging, Programming | Tagged , , | 14 Comments

Windows Performance Analyzer, From Store or SDK

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

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

Arranging Invisible Icons in Quadratic Time

Near the end of January I was pointed to a twitter thread where a Windows user with a powerful machine was hitting random hangs in explorer. Lots of unscientific theories were being proposed. I don’t generally do random analysis of … Continue reading

Posted in Investigative Reporting, Performance, Programming, Quadratic, Rants, Symbols | Tagged , | 18 Comments

Windows Timer Resolution: The Great Rule Change

The behavior of the Windows scheduler changed significantly in Windows 10 2004 (aka, the April 2020 version of Windows), in a way that will break a few applications, and there appears to have been no announcement, and the documentation has … Continue reading

Posted in Uncategorized | Tagged , | Leave a comment