danluu.comadded August 2026
Dan Luu2 Feb 2022
This was co-authored with Yao Yue This is a collection of information on severe (SEV-0 or SEV-1, the most severe incident classifications) incidents at Twitter that were at least partially...
Dan Luu6 Dec 2021
This is a pseudo-transcript (actual words modified to be more readable than a 100% faithful transcription) of a short lightning talk I did at Twitter a year or two ago, on pitfalls of how we use...
Dan Luu22 Nov 2021
Here's a list of errors on this blog that I think were fairly serious. While what I think of as serious is, of course, subjective, I don't think there's any reasonable way to avoid that because...
Dan Luu15 Nov 2021
One of the most common mistakes I see people make when looking at data is incorrectly using an overly simplified model.
Dan Luu8 Nov 2021
Three major tools that companies have to influence behavior are incentives, process, and culture.
Dan Luu21 Oct 2021
People frequently think that I'm very stupid. I don't find this surprising, since I don't mind if other people think I'm stupid, which means that I don't adjust my behavior to avoid seeming stupid...
Dan Luu18 Oct 2021
It's common to see people advocate for learning skills that they have or using processes that they use.
Dan Luu15 Oct 2021
A common topic of discussion among my close friends is where the bottlenecks are in our productivity and how we can execute more quickly.
Dan Luu29 Sept 2021
An alternate title for this post might be, "Twitter has a kernel team!?". At this point, I've heard that surprised exclamation enough that I've lost count of the number times that's been said to me...
Dan Luu27 Aug 2021
A question I get asked with some frequency is: why bother measuring X, why not build something instead?
Dan Luu29 Dec 2020
In the classic 1986 essay, No Silver Bullet, Fred Brooks argued that there is, in some sense, not that much that can be done to improve programmer productivity.
Dan Luu30 Jun 2020
Any time you have a benchmark that gets taken seriously, some people will start gaming the benchmark. Some famous examples in computing are the CPU benchmark specfp and video game benchmarks.
Dan Luu2 Jun 2020
This is an archive of an old pseudonymously written post from the 90s from someone whose former pseudonym seems to have disappeared from the internet.
Dan Luu31 May 2020
A lot of people seem to think that distributed tracing isn't useful, or at least not without extreme effort that isn't worth it for companies smaller than FB.
Dan Luu30 May 2020
We spent one day building a system that immediately found a mid 7 figure optimization (which ended up shipping).
Dan Luu11 Mar 2020
I've been comparing notes with people who run corporate engineering blogs and one thing that I think is curious is that it's pretty common for my personal blog to get more traffic than the entire...
Dan Luu3 Mar 2020
My hobby: opening up McIlroy’s UNIX philosophy on one monitor while reading manpages on the other.
Dan Luu18 Feb 2020
If you read any personal finance forums late last year, there's a decent chance you ran across a question from someone who was desperately trying to lose money before the end of the year.
Dan Luu7 Feb 2020
Reaching 95%-ile isn't very impressive because it's not that hard to do. I think this is one of my most ridiculable ideas. It doesn't help that, when stated nakedly, that sounds elitist.
Dan Luu5 Jan 2020
When I ask people at trendy big tech companies why algorithms quizzes are mandatory, the most common answer I get is something like "we have so much scale, we can't afford to have someone...
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