Matt Nielsen
368 posts
Matt Nielsen
@TonyWunderbar
Sr. Software Engineer, Optimus and Robotaxi @Tesla. Opinions are my own.
/usr/local/bin Katılım Eylül 2020
123 Takip Edilen67 Takipçiler
In SF for Open Sauce and hosting a meetup for interesting hardware tech people and Formerlings this evening. DM me if you want to come!
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@VicVijayakumar Try mixing worktrees with hermetic bazel c++ projects. I’ve done multiple 600+GB purges in the past 2 months.
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@KodaClement This was an especially hard secret to keep from you Clem. Enjoy!
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The things that C programmers see as normal and unremarkable never cease to amaze me.
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I have never found a single good use for a red-black tree (std::map) in my entire career. All of the data structures I learned in school were useless and all of the useful ones I learned outside of class. 😅
Daniel Lemire@lemire
An important skill in software programming is to be able to balance a red-black tree on paper. I practice every day.
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Hi. Expert here of high performance infrastructure at massive scale here.
One cause is the "truncated send()" bug. The Sockets send() function queues up the data in kernel buffers. When the kernel runs out of buffers, send() will return having queued only part of the data, returning the number of bytes queued.
It works like this according to the spec on all systems (Windows, Linux, macOS, etc.). You are supposed to check the return value, most don't.
Thus, you may see it send the data and then close the connection, not understanding that not all the data was actually stored in the kernel buffers.
It's a far more common bug than people realize because it'll pass through almost all automated testing. You have to heavily load a server to the point where kernel buffers are all in use before you can detect it, which is beyond the scale of typical Continuous Integration unit/regression tests.
It can continue right through production, because a lot of things correct it, such as automatically restarting a transaction if there's an intermittent failure.
You can see the problem easily looking at the outer SSL headers, by tracking record length fields and error messages.
But if it's the last record before terminating the connection, then you can easily diagnose it.
The problem described is confusing. It talks about half a request when the rest of the text sounds like half a response.
David Gu@davidgu
we run 18 million EC2 instances per month. At our scale, we see very rare bugs very frequently. Last week, we received *half* an HTTP request. Not a HTTP 206, literally half a request. Content-Length was 2350 bytes. Body was actually 1200 bytes, and was truncated mid json doc.
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It is under appreciated the fact that Tesla engineers are able to test Full Self-Driving at home, road trips, running errands — literally every second of their lives inside a Tesla.
I went to a dinner once where a few people work at autonomous vehicle companies. They rarely put their butt in their own build, let alone drive them anywhere after work.
Thus ride quality and experience are a myth to them.
In contrast, we put our butt in the seat, literally “working ass off” every day, and getting unfiltered feedback from the spouses 😆.
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Matt Nielsen retweetledi
Matt Nielsen retweetledi
meteorologists love sharing plots which are impenetrable beyond parody then saying smth like “May God have mercy on our souls”
Mitch West@SCweather_wx
WOAH.. We might just be heading for glory folks.
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Matt Nielsen retweetledi
The average Creality bed
flowstate@k_flowstate
It's sad that almost all of you don't know what this image represents
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@KodaClement Bro I do this all the time except it’s like an officer telling me i failed grade 6 english and need to go back school
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Matt Nielsen retweetledi
There’s a game dev somewhere throwing a case of beer on a table and celebrating with his design team 😭
Scope@FaZeScope
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@YunTaTsai1 So glad he gave that presentation, it shows how deep we’re going into real world AI.
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@KodaClement @YunTaTsai1 Why would you need to process it clemmy? 🤔
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@YunTaTsai1 how are yall processing the image then? Surely you need decoders for the bitstream?
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People probably do not realize how baller move to delete image signal processor is. 😆
If you ask any SoC designer they would probably drop their jaws.
But for a AI purely designed around “Photon Count” it is just a dead area. When we say “Photons” as input, we really mean it.
Sawyer Merritt@SawyerMerritt
Elon Musk on Tesla's next-gen HW5 (AI5) chip: "We are actually going to focus TSMC and Samsung on AI5. The chip design is an amazing design. I have spent almost every weekend the last few months with the chip design on AI5. By some metrics, it will be 40X better than AI4. We have a detailed understanding of the entire stack. With AI5, we deleted the legacy GPU. It basically is a GPU. We also deleted the image signal processor; This is a beautiful chip. I've poured so much life energy into this personally. It will be a real winner."
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Canadian thanksgiving is just around the corner
Who’s in SF and wants a hat?
👇 @ reply and ill dm you!
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