Log inSign up
Dan Luu
5,595 posts
@danluu

Dan Luu

@danluu
Active on mastodon.social/@danluu; also trying out bsky.app/profile/danluu…
danluu.com
Joined December 2008
44
Following
46.7K
Followers
RepliesRepliesRepostsRepostsMediaMedia

Log in or sign up for X

See what’s happening and join the conversation

Continue with phone
or
Log in with username or email
Terms·Privacy·Cookies·Accessibility·Ads Info·© 2026 X Corp.
  • Pinned
    @danluu
    Dan Luu
    @danluu
    Dec 24, 2017
    Computer latency: 1977-2017 danluu.com/input-lag/
    89
  • @danluu
    Dan Luu
    @danluu
    Aug 29
    Bug Blindness: danluu.com/bug-blind/
    I used to wonder why I see so many more bugs than most people. I easily observe hundreds to thousands of bugs per week and nothing seems to work, but most people I talk to don't see anything like this. For a long time, I thought this had something to do with how I use computers but, over time, I've realized that it's mostly that people are hitting the same bugs and don't notice.

If you're not a programmer, that's probably a better way to see the world, but I think curing quality/bug blindness is helpful for programmers. I've done this with a lot of friends and acquaintances (just by pointing out bugs). After a few weeks, people who are so inclined tend to start noticing bugs as well.

Because I notice these kinds of things, I've had multiple jobs where directors/VPs/execs/etc. sometimes ask me to evaluate something when they want an actual opinion from someone who is relatively likely to notice issues (and fix them or drive fixes for them if necessary). Sometimes I won't find any i...
    17
  • @danluu
    Dan Luu
    @danluu
    Aug 21
    There's no reason for software to be slow anymore: danluu.com/perf-opt/
    The other day, I saw a viral tweet saying that people talking about how LLMs are causing slow, bloated, code are going to eat crow once they re-write everything in super-optimized assembly. We're not quite at the point where we want to write everything in assembly, but some variant of what Nolan Lawson said about testing, you can choose how many bugs you want now, which I less eloquently noted here, is becoming more true for performance.

In response to a comment in my last post that the cost of formerly specialized performance work has dropped by many orders of magnitude and performance work that used to require a person or team that had a rare set of skills can be done by anyone who can type a few sentences1, which means that you can do all sorts of optimizations that used to be too expensive to be worthwhile for all but the largest scale or most lucrative projects, Marc Brooker responded with

    Completely agree with your closing point. Dynamic custom software, fitted to a part...
    14
  • @danluu
    Dan Luu
    @danluu
    Aug 17
    The benchmarkpocalypse: danluu.com/benchpocalypse/
    There's been a lot of talk about the vulnpocalypse, to which I don't have much to add because I'm not a security person, but I haven't seen much discussion on the closely related (and to be fair, less serious, issue), the benchmarkpocalypse.

While it's become easier than ever to make serious performance gains, it's also become easier than ever to reward hack a benchmark and make fake performance gains. The former is probably happening quietly across many different companies, but the latter is something I see at least once a week nowadays. Someone will claim they optimized X and got some huge performance improvement over existing software, but, when you look at it, what they did was make some optimization that improves benchmark performance without actually improving real-world performance. This is often some kind of "we rewrote X in Rust"1 project or a new startup that's looking to either fundraise or sell something, but it happens on other kinds of projects as well2.

Rather than ...
    5
  • @danluu
    Dan Luu
    @danluu
    Aug 10
    What programming languages are coding agents best at? danluu.com/pl-tokens/
    43