Skip to content
By using Twitter’s services you agree to our Cookies Use. We and our partners operate globally and use cookies, including for analytics, personalisation, and ads.

This is the legacy version of twitter.com. We will be shutting it down on June 1, 2020. Please switch to a supported browser, or disable the extension which masks your browser. You can see a list of supported browsers in our Help Center.

  • Home Home Home, current page.
  • About

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @
  • Language: English
    • Bahasa Indonesia
    • Bahasa Melayu
    • Català
    • Čeština
    • Dansk
    • Deutsch
    • English UK
    • Español
    • Filipino
    • Français
    • Hrvatski
    • Italiano
    • Magyar
    • Nederlands
    • Norsk
    • Polski
    • Português
    • Română
    • Slovenčina
    • Suomi
    • Svenska
    • Tiếng Việt
    • Türkçe
    • Ελληνικά
    • Български език
    • Русский
    • Српски
    • Українська мова
    • עִבְרִית
    • العربية
    • فارسی
    • मराठी
    • हिन्दी
    • বাংলা
    • ગુજરાતી
    • தமிழ்
    • ಕನ್ನಡ
    • ภาษาไทย
    • 한국어
    • 日本語
    • 简体中文
    • 繁體中文
  • Have an account? Log in
    Have an account?
    · Forgot password?

    New to Twitter?
    Sign up
pcwalton's profile
Patrick Walton
Patrick Walton
Patrick Walton
@pcwalton

Tweets

Patrick Walton

@pcwalton

Research engineer at Mozilla

San Francisco, CA
pcwalton.github.io
Joined November 2009

Tweets

  • © 2020 Twitter
  • About
  • Help Center
  • Terms
  • Privacy policy
  • Imprint
  • Cookies
  • Ads info
Dismiss
Previous
Next

Go to a person's profile

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @

Promote this Tweet

Block

  • Tweet with a location

    You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more

    Your lists

    Create a new list


    Under 100 characters, optional

    Privacy

    Copy link to Tweet

    Embed this Tweet

    Embed this Video

    Add this Tweet to your website by copying the code below. Learn more

    Add this video to your website by copying the code below. Learn more

    Hmm, there was a problem reaching the server.

    By embedding Twitter content in your website or app, you are agreeing to the Twitter Developer Agreement and Developer Policy.

    Preview

    Why you're seeing this ad

    Log in to Twitter

    · Forgot password?
    Don't have an account? Sign up »

    Sign up for Twitter

    Not on Twitter? Sign up, tune into the things you care about, and get updates as they happen.

    Sign up
    Have an account? Log in »

    Two-way (sending and receiving) short codes:

    Country Code For customers of
    United States 40404 (any)
    Canada 21212 (any)
    United Kingdom 86444 Vodafone, Orange, 3, O2
    Brazil 40404 Nextel, TIM
    Haiti 40404 Digicel, Voila
    Ireland 51210 Vodafone, O2
    India 53000 Bharti Airtel, Videocon, Reliance
    Indonesia 89887 AXIS, 3, Telkomsel, Indosat, XL Axiata
    Italy 4880804 Wind
    3424486444 Vodafone
    » See SMS short codes for other countries

    Confirmation

     

    Welcome home!

    This timeline is where you’ll spend most of your time, getting instant updates about what matters to you.

    Tweets not working for you?

    Hover over the profile pic and click the Following button to unfollow any account.

    Say a lot with a little

    When you see a Tweet you love, tap the heart — it lets the person who wrote it know you shared the love.

    Spread the word

    The fastest way to share someone else’s Tweet with your followers is with a Retweet. Tap the icon to send it instantly.

    Join the conversation

    Add your thoughts about any Tweet with a Reply. Find a topic you’re passionate about, and jump right in.

    Learn the latest

    Get instant insight into what people are talking about now.

    Get more of what you love

    Follow more accounts to get instant updates about topics you care about.

    Find what's happening

    See the latest conversations about any topic instantly.

    Never miss a Moment

    Catch up instantly on the best stories happening as they unfold.

    1. Steve Canon‏ @stephentyrone 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @pkhuong @jckarter and

      Was thinking x86 5-level tables (57 bits) =)

      1 reply 0 retweets 0 likes
    2. Paul Khuong‏ @pkhuong 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @stephentyrone @jckarter and

      ITT: apple thumbs its nose at the kaiser!

      1 reply 0 retweets 0 likes
    3. Steve Canon‏ @stephentyrone 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @pkhuong @jckarter and

      It's ok though, malloc allocations are 16-byte aligned on Darwin, so that still leaves 11 bits to play with.

      1 reply 0 retweets 2 likes
    4. Paul Khuong‏ @pkhuong 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @stephentyrone @jckarter and

      I like how the platform that aligns heap allocations to 16 wasn't sure about STACK ALIGNMENT for a while.

      1 reply 0 retweets 1 like
    5. Steve Canon‏ @stephentyrone 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @pkhuong @jckarter and

      Stack alignment has always been 16B too, except for 32b iOS because /reasons/

      3 replies 0 retweets 0 likes
    6. Steve Canon‏ @stephentyrone 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @stephentyrone @pkhuong and

      (For sufficiently weak notions of “always”)

      1 reply 0 retweets 1 like
    7. Paul Khuong‏ @pkhuong 26 Feb 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @stephentyrone @jckarter and

      OK, so maybe we have to share some of the blame with artisanal stack frames.

      2 replies 0 retweets 2 likes
    8. Hugo Firth‏ @hugofirth 27 Feb 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @pkhuong @stephentyrone and

      Ok. Clearly I have kicked a fascinating hornet’s nest and need to learn more about cutting edge ARC :-) Can anyone suggest good resources/papers?

      1 reply 0 retweets 1 like
    9. Hugo Firth‏ @hugofirth 27 Feb 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @hugofirth @pkhuong and

      Specifically interested in examples of efficient cycle detection without user hints and intervention. Also sharing references between threads without atomic ops

      1 reply 0 retweets 0 likes
    10. Joe Groff‏ @jckarter 27 Feb 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @hugofirth @pkhuong and

      @graydon_pub or @pcwalton might have some good papers on hand; early Rust had some fancy cycle detection and heap sharing.

      2 replies 0 retweets 0 likes
      Patrick Walton‏ @pcwalton 27 Feb 2019
      • Report Tweet
      • Report NetzDG Violation
      Replying to @jckarter @hugofirth and

      AFAIK Bacon 2001 is still state of the art in cycle collection: https://researcher.watson.ibm.com/researcher/files/us-bacon/Bacon01Concurrent.pdf … Graydon is more of an expert here though, having shipped the most widely used implementation of cycle collection in industry :)

      8:55 AM - 27 Feb 2019
      • 4 Likes
      • Felipe O. Carvalho Gordon Brander Vivitsu Maharaja Joe Groff
      3 replies 0 retweets 4 likes
        1. New conversation
        2. Patrick Walton‏ @pcwalton 27 Feb 2019
          • Report Tweet
          • Report NetzDG Violation
          Replying to @pcwalton @jckarter and

          (For what it’s worth, I think RC was the right choice for Swift, though I prefer GC even for resource constrained environments.)

          1 reply 0 retweets 0 likes
        3. Joe Groff‏ @jckarter 27 Feb 2019
          • Report Tweet
          • Report NetzDG Violation
          Replying to @pcwalton @hugofirth and

          Making gc-managed allocations async, like some of the rust-gc libraries do, might change the game a lot. That could help keep GC managed operations out of non-async C interop or realtime/critical sections

          0 replies 0 retweets 1 like
        4. End of conversation
        1. New conversation
        2. Graydon Hoare‏ @graydon_pub 27 Feb 2019
          • Report Tweet
          • Report NetzDG Violation
          Replying to @pcwalton @jckarter and

          Haha I just did the initial sketch (and this was before we had a testsuite, when you got to land code "when it compiled"); a much wider cast of long-suffering gecko hackers did all the heavy lifting. But: everything RC I know of that collects cycles does _some_ backup tracing...

          1 reply 0 retweets 5 likes
        3. Graydon Hoare‏ @graydon_pub 27 Feb 2019
          • Report Tweet
          • Report NetzDG Violation
          Replying to @graydon_pub @pcwalton and

          It's a kinda high-dimensional design space. Peak and steady memory pressure, latency, throughput, fragmentation, code size, etc. All of which are super sensitive to cache and hardware concurrency issues. In RC and tracing/copying regimes, alike. So the ground is always shifting.

          1 reply 0 retweets 2 likes
        4. 3 more replies
        1. Andrew McCreight‏ @amccreight 27 Feb 2019
          • Report Tweet
          • Report NetzDG Violation
          Replying to @pcwalton @jckarter and

          "Efficient On-the-Fly Cycle Collection" by Paz et al is a little more recent (2005) and fancier. (Firefox ships an incremental CC, but only single threaded.)

          0 replies 0 retweets 2 likes
          Thanks. Twitter will use this to make your timeline better. Undo
          Undo

      Loading seems to be taking a while.

      Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.

        Promoted Tweet

        false

        • © 2020 Twitter
        • About
        • Help Center
        • Terms
        • Privacy policy
        • Imprint
        • Cookies
        • Ads info