Category Archives: Programming

63 Cores Blocked by Seven Instructions

Posted on October 20, 2019 by brucedawson

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

When Your Profiler Lies

Posted on December 9, 2018 by brucedawson

Last week I wrote about the performance consequences of inadvertently loading gdi32.dll into processes that are created and destroyed at very high rates. This week I want to share some techniques for digging deeper into this behavior, and the odd … Continue reading →

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

A Not-Called Function Can Cause a 5X Slowdown

Posted on December 3, 2018 by brucedawson

Subtitle: Making Windows Slower Part 3: Process Destruction In the summer of 2017 I wrestled with a Windows performance problem. Process destruction was slow, serialized, and was blocking the system input queue, leading to repeated short mouse-movement hangs when building … Continue reading →

Posted in Investigative Reporting, Performance, Programming | Tagged , , | Leave a comment

Making Windows Slower Part 2: Process Creation

Posted on October 15, 2018 by brucedawson

Windows has long had a reputation for slow file operations and slow process creation. Have you ever wanted to make these operations even slower? This weeks’ blog post covers a technique you can use to make process creation on Windows … Continue reading →

Posted in Code Reliability, Investigative Reporting, Performance, Programming, Quadratic | Tagged , , | 7 Comments

Making Windows Slower Part 1: File Access

Posted on April 17, 2018 by brucedawson

Windows has long had a reputation for slow file operations and slow process creation. Have you ever wanted to make these operations even slower? This weeks’ blog post covers a technique you can use to make all file operations on … Continue reading →

Posted in Investigative Reporting, Performance, Programming, xperf | Tagged , , | 18 Comments

Compiler bug? Linker bug? Windows Kernel bug.

Posted on February 25, 2018 by brucedawson

See the end of the post for an October 2018 bug fix update, or read the whole story: Flaky failures are the worst. In this particular investigation, which spanned twenty months, we suspected hardware failure, compiler bugs, linker bugs, and … Continue reading →

Posted in Debugging, Investigative Reporting, Programming | Tagged , , , | 57 Comments

Zombie Processes are Eating your Memory

Posted on February 11, 2018 by brucedawson

Zombies probably won’t consume 32 GB of your memory like they did to me, but zombie processes do exist, and I can help you find them and make sure that developers fix them. Tool source link is at the bottom. … Continue reading →

Posted in Debugging, Investigative Reporting, Performance, Programming, Rants | Tagged , , | 74 Comments

Delete an inline function, save 794 kB

Posted on January 22, 2017 by brucedawson

In the previous episode of “Simple Changes to Shrink Chrome” I discussed how deleting ‘const’ from a few key locations could lead to dramatic size savings, due to a VC++ compiler quirk. In this episode I’ll show how deleting an … Continue reading →

Posted in Performance, Programming, Visual Studio | Tagged , , | 13 Comments

Add a const here, delete a const there…

Posted on January 8, 2017 by brucedawson

Update, February 2019: Two years later the VC++ bug I reported here still exists, even in VS 2019 preview. However Chromium no longer builds with VC++ so I’m reverting the changes where I deleted const in order to make some … Continue reading →

Posted in Performance, Programming, Visual Studio | Tagged , , | 27 Comments

VC++ /arch:AVX option – unsafe at any speed

Posted on December 5, 2016 by brucedawson

Microsoft’s VC++ compiler has an option to generate instructions for new instruction sets such as AVX and AVX2, which can lead to more efficient code when running on compatible CPUs. So, an obvious tactic is to compile critical math-heavy functions … Continue reading →

Posted in Programming, Visual Studio | Tagged , , , , | 35 Comments