brucedawson 
This story begins, as they so often do, when I noticed that my machine was behaving poorly. My Windows 10 work machine has 24 cores (48 hyper-threads) and they were 50% idle. It has 64 GB of RAM and that … Read more
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 … Read more
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 … Read more
Zeroing out a CPU register seems like the simplest and most basic operation imaginable, but in fact x86 CPUs contain a surprising amount of special logic to make this operation run smoothly. The most obvious way of zeroing an x86 … Read more
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 … Read more
The recent reveal of Meltdown and Spectre reminded me of the time I found a related design bug in the Xbox 360 CPU – a newly added instruction whose mere existence was dangerous. Back in 2005 I was the Xbox … Read more