Comparison of Malloc() Algorithms
88 points by egberts1 2 days ago | 22 comments
  • benjojo12 6 hours ago |
    ERR_SSL_VERSION_OR_CIPHER_MISMATCH on my phone it seems?
    • j4k0bfr 5 hours ago |
      Same, from Chrome on Android
    • Rygian 3 hours ago |
      TLS_CHACHA20_POLY1305_SHA256 (256 bit keys, TLS 1.3) successfully negotiated here (Firefox esr 140.14.0).
  • Nnnes 6 hours ago |
    https://web.archive.org/web/20260915165314/https://egbert.ne...

    Funny SSL setup. Explanation from here https://news.ycombinator.com/item?id=49133598

    > Oh, certain browser will not work with this blog if it cannot negotiate ONLY for Cha-Cha/Poly. It's by design as a showcase of why that particular web browser refuses to do that.

    I assume the "particular web browser" is Chromium, which won't load it on any OS I've tried. On Windows, Firefox and the built-in curl.exe also refuse to connect.

    • bom-d-van 5 hours ago |
      legend.
    • ncruces 4 hours ago |
      Thanks for the link.

      Article makes it look like nothing happened in the embed/low-memory/single-threaded malloc space in decades since Doug Lea's malloc.

      I just implemented TLSF for my minimal Wasm libc: fragmentation is just as good, performance is a lot more consistent (and on average better), for a significant reduction in code size.

      http://www.gii.upv.es/tlsf/index.html

      https://github.com/ncruces/wasm2go/blob/main/libc-gen/c/mall...

      • egberts1 an hour ago |
        A great idea for another article. A focus, on embedded and malloc()

        I do do have a malloc() benchmark but it is in bad shape and directories have not coalesce nicely yet, tor a single run or a menu-driven one.

    • egberts1 an hour ago |
      It keeps certain web scrapers and inline transparent proxies/IDS/XNS from fetching, 100%

      Certain browsers will suffer. Meh.

  • ligarota 5 hours ago |
    Please write a "how to setup SSL" article
    • eqvinox 4 hours ago |
      It seems to be intentional & if somebody wants to make a statement about TLS with their personal website that's their choice to make and execute.
      • entrope 2 hours ago |
        On the bright side, lots of people will be saved from reading bad prose like "Malloc (libc) is the worst memory allocation API to use" and "Programs should avoid, if possible, allocating/deallocating memory too often". (By definition, "too often" means it can possibly be avoided, and usually that it can practically be avoided.)
      • egberts1 2 hours ago |
        Yes
    • egberts1 2 hours ago |
      No
  • Someone 4 hours ago |
    Not a good article, IMO.

    FTA: “When multiple threads simultaneously allocate or deallocate memory from the allocator, the allocator will serialize them. Programs making intensive use of the allocator actually slow down as the number of processors increases.”

    The article does later retract on that, but that’s no reason to lead with such a blatantly false (with current allocators) statement.

    Also FTA “In 2006, a third pool was introduced (after operating system memory pool and library-based memory pool) called the “arena”. Arena is a jemalloc-term”

    Jemalloc is from around 2005 (http://jemalloc.net/), the idea of arenas is from the 1960s, and Wikipedia claims the term was coined in 1990 (https://en.wikipedia.org/wiki/Region-based_memory_management...), and the linked paper (https://www.cs.princeton.edu/techreports/1988/191.pdf) is from 1988.

    Then, a typo: “as well as memory tied to specific to each of the multiple CPU core or even CPU infinity.”

    “Infinity” should be “affinity” there.

    • eqvinox 4 hours ago |
      The tables look mostly correct, and that's what I'll be bookmarking this for… I don't think I've seen any elsewhere that are this extensive (in both axis, total allocators covered & details per allocator).
      • egberts1 an hour ago |
        Thank you.

        I got tired of reading AI prose so I compiled and wrote it from my collections of others' whitepapers.

        As a "For Reference Only", at the very least, for me.

        As usual, anyone is welcome to improve upon it under CC BY-NC-SA.

    • skavi 2 hours ago |
      yup and the characterization of each allocator is so fuzzy, with zero methodology provided.

      allocators are so simple to just swap into your program. if you can put together a few representative workloads, you should just try out a few allocators and profile whatever metrics you care about.

      • imp0cat an hour ago |
        And finally end up with either jemalloc or possibly mimalloc. ;)
        • egberts1 an hour ago |
          Invariably so but I'm mulling over malloc()s on embedded topic now.
      • zX41ZdbW 25 minutes ago |
        ClickHouse has been tested with jemalloc, mimalloc, tcmalloc (both variants), rpmalloc, lfalloc, hualloc, and ended up using jemalloc after a few patches and bug fixes.
    • egberts1 an hour ago |
      Thank you for the critique.

      Compilations are hard to get 100% right.

  • AnimalMuppet 7 minutes ago |
    Couldn't read the article (ERR_SSL_VERSION_OR_CIPHER_MISMATCH, Chrome on Windows). But I'm remembering something a coworker told me some time around... 1991 to 1993, maybe? Forgive me if I repeat some of what the article says - I did try to read it!

    While he was at the university, they were experimenting with different kind of mallocs. One was called the "buddy" malloc. It kept a list of free blocks of various sizes, and when you asked for a block and it didn't have one, it asked the OS for twice as much as you asked for. From the rest, it made another block (identical to yours, called the "buddy" block), and put it on the free list of that size.

    Well, they experimented with a similar algorithm, but the idea was that most requests were small. So it took the buddy block and broke it into smaller pieces, one half the size of the request, one a quarter the size, and so on, and put those on their respective free lists. They called this the "donner" malloc, because you carved up your buddy.

    From the way my coworker smiled, I think he thought it was amusing, but I don't think he was making it up.