Category Archives: Programming

O(n^2), again, now in WMI

Posted on December 8, 2019 by

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, Rants, uiforetw, xperf | Tagged , , , , | 43 Comments

Heap Snapshots–Tracing All Heap Allocations

Posted on October 27, 2019 by

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 , | 13 Comments

63 Cores Blocked by Seven Instructions

Posted on October 20, 2019 by

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, uiforetw, xperf | Tagged , , | 37 Comments

When Your Profiler Lies

Posted on December 9, 2018 by

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 , , | 20 Comments

A Not-Called Function Can Cause a 5X Slowdown

Posted on December 3, 2018 by

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 , , | 13 Comments

Making Windows Slower Part 2: Process Creation

Posted on October 15, 2018 by

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 | Tagged , , | 20 Comments

Making Windows Slower Part 1: File Access

Posted on April 17, 2018 by

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 , , | 25 Comments