Aleksey Shipilëv

@shipilev

Currently: developing and maintaining OpenJDK at Red Hat. This account is run by a human, expect occasional shitposts. Send emails for important stuff.

Potsdam, Germany
shipilev.net
Joined April 2011
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  1. Retweeted
    Apr 13

    "Java Objects Inside Out": large-ish treatise on how Hotspot deals with internal object layouts, and what it can mean for low-level library developers.

    11 replies 167 retweets 451 likes
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  2. 2 hours ago

    It is kinda adorable and on-brand that identifiers for different endinannesses are all over the place. Which one is it: ppc64el or ppc64le, mips64el or mips64le?

    2 replies 4 likes
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  3. Nov 21

    Would I consider an ARM64 laptop for my future ultrabook upgrades? Sure, why not -- longevity with reasonable perf is important. Would I fantasize about an ARM64 laptop replacing my desktops? Surely not --laptops would still be very slow for my daily chores.

    2 replies 19 likes
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  4. Nov 21

    Building full OpenJDK on: - 3900X desktop: 4 min * 95W =~ 23 kJ - i5-4120U ultrabook: 35 min * 25W =~ 53 kJ - Raspberry Pi 4: 50 min * 5W =~15 kJ Sure, ARM64 laptops are exciting, but mostly because laptops (especially older ones) really suck in both speed and efficiency.

    5 replies 7 retweets 52 likes
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  5. Nov 20

    Happy Friday Pushes Day!

    1 reply 10 likes
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  6. Retweeted
    Nov 20

    Прям всегда мечтал осуществить

    6 retweets 13 likes
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  7. Nov 20

    If I ever dabble in creating a formal verification language, I put dibs on Verylong as the name.

    4 replies 1 retweet 12 likes
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  8. Retweeted
    Nov 19

    Engineering: "Make sure to not put solder mask on top of the high speed 56Gbps differential traces to reduce dielectric losses" Manufacturing: "lol, sticker"

    12 replies 221 retweets 1,190 likes
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  9. Nov 18

    for (int i = 0; i < method_count; i++) ... error: ‘for’ loop initial declarations are only allowed in C99 mode. (shakes fist in the air)

    2 replies 39 likes
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  10. Nov 18

    Don't be afraid of tiny methods, they said. The compilers would take care of them, they said. True, if you have a compiler! Otherwise, prepare to spend much more time during the interpreter-only build computing SHA digests.

    4 replies 1 retweet 38 likes
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  11. Nov 18

    Wednesday fun: Zero VM is the slow C++ interpreter that cannot allocate very fast, which makes Epsilon GC happy. A match made in heaven!

    1 reply 2 retweets 9 likes
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  12. Nov 17

    Hey look, it is indeed there. Can now switch our 11u nightlies with the out-of-the-box OpenJDK for CLion/IDEA.

    8 likes
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  13. Nov 17

    Looks like Debian enabled Shenandoah GC in their OpenJDK 11.0.9 packages. That great, since most of my boxes use Debian/Ubuntu... for historical reasons. :P

    2 replies 20 likes
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  14. Nov 17

    OpenJDK 11.0.10 (Jan 2021) bumps MaxInlineLevel to 15, following the initial change in JDK 14, and Corretto 11u shipping with it for quite a while.

    2 replies 10 retweets 42 likes
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  15. Nov 16

    Looks like I managed to backport this to all active JDK releases: -XX:+AbortVMOnCompilationFailure, or "Hey JVM, if you are about to drop any C2 candidate method to C1 or interpreter, just crash instead, would ya?" Saves me countless hours in perf work.

    2 replies 7 retweets 51 likes
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  16. Nov 16

    Tired: looking at console output for benchmark progress. Wired: looking at labs power consumption for benchmark progress.

    3 replies 40 likes
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  17. Nov 15

    The recurrent debate about having a laptop or a desktop almost inevitably hinges on an odd presupposition that you are not allowed to have both.

    8 replies 1 retweet 56 likes
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  18. Nov 13

    "Network is a computer", который мы заслужили.

    3 likes
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  19. Nov 12

    Things I did not want to learn today: how Java, and then Hotspot runtime stubs, and then C compilers, and finally x87 FPU all handle signalling NaNs.

    4 replies 1 retweet 44 likes
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  20. Nov 11

    Transplanted qemu-debootstrap cross-compilation configs from CI to GH actions for OpenJDK -- -- which gives all OpenJDK PRs foreign architectures build tests. Whoosh.

    3 replies 1 retweet 28 likes
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  21. Nov 11

    My CV: "Hands-on expertise with high load systems". My actual system: "CPU cores: 64. Load average: 490.17, 382.89, 322.93."

    3 replies 2 retweets 60 likes
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