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At a first glance, the table seems about right, in that the sites that feel slow unless you have a super fast device show up as slow in the table (as in, max(LCP*,CPU)) is high on lower-end devices). When I polled folks about what platforms they thought would be fastest and slowest on our slow devices (Mastodon, Twitter, Threads), they generally correctly predicted that Wordpress and Ghost would b
Marginalia does relatively well by sometimes providing decent but not great answers and then providing no answers or very obviously irrelevant answers to the questions it can't answer, with a relatively low rate of scams, lower than any other search engine (although, for these queries, ChatGPT returns zero scams and Marginalia returns some). Interestingly, Mwmbl lets users directly edit search res
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 attributed to cache from the time Twitter started using its current incident tracking JIRA (2012) to date (2022), with one bonus incident from before 2012. Not including the bonus incident, there were 6 SEV-0s a
It's common to see people advocate for learning skills that they have or using processes that they use. For example, Steve Yegge has a set of blog posts where he recommends reading compiler books and learning about compilers. His reasoning is basically that, if you understand compilers, you'll see compiler problems everywhere and will recognize all of the cases where people are solving a compiler
Perf is probably the most widely used general purpose performance debugging tool on Linux. There are multiple contenders for the #2 spot, and, like perf, they're sampling profilers. Sampling profilers are great. They tend to be easy-to-use and low-overhead compared to most alternatives. However, there are large classes of performance problems sampling profilers can't debug effectively, and those p
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. For example, here are a couple of public conversations that sound like a number of private conversations I've had. Sure, there's value somewhere, but it costs too much to unlock. I think this overestimates how much work it is to get a lot of
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 corp eng blog for a company with a nine to ten figure valuation and it's not uncommon for my blog to get an order of magnitude more traffic. I think this is odd because tech companies in that class often
This table has the number of command line options for various commands for v7 Unix (1979), slackware 3.1 (1996), ubuntu 12 (2015), and ubuntu 17 (2017). Cells are darker and blue-er when they have more options (log scale) and are greyed out if no command was found. We can see that the number of command line options has dramatically increased over time; entries tend to get darker going to the right
This is a response to the following question from David Albert: My mental model of CPUs is stuck in the 1980s: basically boxes that do arithmetic, logic, bit twiddling and shifting, and loading and storing things in memory. I'm vaguely aware of various newer developments like vector instructions (SIMD) and the idea that newer CPUs have support for virtualization (though I have no idea what that me
Let's write a malloc and see how it works with existing programs! This tutorial is going to assume that you know what pointers are, and that you know enough C to know that *ptr dereferences a pointer, ptr->foo means (*ptr).foo, that malloc is used to dynamically allocate space, and that you're familiar with the concept of a linked list. For a basic intro to C, Pointers on C is one of my favorite b
2015 was a pretty good year for Intel. Their quarterly earnings reports exceeded expectations every quarter. They continue to be the only game in town for the serious server market, which continues to grow exponentially; from the earnings reports of the two largest cloud vendors, we can see that AWS and Azure grew by 80% and 100%, respectively. That growth has effectively offset the damage Intel h
Here's a conversation I keep having: Someone: Did you hear that Facebook/Google uses a giant monorepo? WTF! Me: Yeah! It's really convenient, don't you think? Someone: That's THE MOST RIDICULOUS THING I've ever heard. Don't FB and Google know what a terrible idea it is to put all your code in a single repo? Me: I think engineers at FB and Google are probably familiar with using smaller repos (does
2011 As above, the results are sorted by latency and color-coded from green to yellow to red to black as devices get slower. Also as above, the year gets purple-er (and darker) as the device gets older. If we exclude the game boy color, which is a different class of device than the rest, all of the quickest devices are Apple phones or tablets. The next quickest device is the blackberry q10. Althou
This table is for all code in linux under fs. Each row shows data for calls of one function. For each year, the leftmost cell shows the number of calls that do something with the return value over the total number of calls. The cell to the right shows the percentage of calls that do something with the return value. “Do something” is used very loosely here -- branching on the return value and then
The latency measurements are the time from when the key starts moving to the time when the USB packet associated with the key makes it out onto the USB bus. Numbers are rounded to the nearest 5 ms in order to avoid giving a false sense of precision. The easterntimes i500 is also sold as the tomoko MMC023. The connection column indicates the connection used. USB FS stands for the usb full speed pro
This is a pseudo-transcript for a talk on branch prediction given at Two Sigma on 8/22/2017 to kick off "localhost", a talk series organized by RC. How many of you use branches in your code? Could you please raise your hand if you use if statements or pattern matching? Most of the audience raises their hands I won’t ask you to raise your hands for this next part, but my guess is that if I asked, h
There’s a great MSR demo from 2012 that shows the effect of latency on the experience of using a tablet. If you don’t want to watch the three minute video, they basically created a device which could simulate arbitrary latencies down to a fraction of a millisecond. At 100ms (1/10th of a second), which is typical of consumer tablets, the experience is terrible. At 10ms (1/100th of a second), the la
Which is faster, keyboard or mouse? A large number of programmers believe that the keyboard is faster for all (programming-related) tasks. However, there are a few widely cited webpages on AskTog which claim that Apple studies show that using the mouse is faster than using the keyboard for everything and that people who think that using the keyboard is faster are just deluding themselves. This mig
A couple years ago, I took a road trip from Wisconsin to Washington and mostly stayed in rural hotels on the way. I expected the internet in rural areas too sparse to have cable internet to be slow, but I was still surprised that a large fraction of the web was inaccessible. Some blogs with lightweight styling were readable, as were pages by academics who hadn’t updated the styling on their websit
There are a lot of “12 CS books every programmer must read” lists floating around out there. That's nonsense. The field is too broad for almost any topic to be required reading for all programmers, and even if a topic is that important, people's learning preferences differ too much for any book on that topic to be the best book on the topic for all people. This is a list of topics and books where
I haven't used a desktop email client in years. None of them could handle the volume of email I get without at least occasionally corrupting my mailbox. Pine, Eudora, and outlook have all corrupted my inbox, forcing me to restore from backup. How is it that desktop mail clients are less reliable than gmail, even though my gmail account not only handles more email than I ever had on desktop clients
This is one of those “N technical things every programmer must read” lists, except that “programmer” is way too broad a term and the styles of writing people find helpful for them are too different for any such list to contain a non-zero number of items (if you want the entire list to be helpful to everyone). So here's a list of some things you might want to read, and why you might (or might not)
The book starts with a story about a time Margaret Hamilton brought her young daughter with her to NASA, back in the days of the Apollo program. During a simulation mission, her daughter caused the mission to crash by pressing some keys that caused a prelaunch program to run during the simulated mission. Hamilton submitted a change request to add error checking code to prevent the error from happe
An acquaintance of mine, let’s call him Mike, is looking for work after getting laid off from a contract role at Microsoft, which has happened to a lot of people I know. Like me, Mike has 11 years in industry. Unlike me, he doesn't know a lot of folks at trendy companies, so I passed his resume around to some engineers I know at companies that are desperately hiring. My engineering friends thought
Looks like it takes six years to gross a U.S. career's worth of income. If you want to adjust for the increased tax burden from earning a lot in a few years, add an extra year. Maybe add one to two more years if you decide to live in the bay or in NYC. If you decide not to retire, lifetime earnings for a 40 year career comes in at almost $10M. One common, but false, objection to this is that your
Jeff Atwood, perhaps the most widely read programming blogger, has a post that makes a case against using ECC memory. My read is that his major points are: Google didn't use ECC when they built their servers in 1999 Most RAM errors are hard errors and not soft errors RAM errors are rare because hardware has improved If ECC were actually important, it would be used everywhere and not just servers.
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