Category Archives: Investigative Reporting

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

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

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 Environment, Investigative Reporting, Performance, Rants | Tagged , | 66 Comments

What Outranks Thread Priority?

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

O(n^2), again, now in WMI

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

63 Cores Blocked by Seven Instructions

I seem to have a habit of writing about super powerful machines whose many cores are laid low by misuse of locks. So. Yeah. It’s that again. But this one seems particularly impressive. I mean, how often do you have … Continue reading

Posted in Investigative Reporting, Performance, Programming, Quadratic, uiforetw, xperf | Tagged , , | 12 Comments