VirtualTam's bookmarks

1. *(char*)0 = 0; - What Does the C++ Programmer Intend With This Code? 2024-03-12

   tags: compiler, hardware/cpu, memory/cache, programming/c, programming/c++

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2. Rust std fs slower than Python!? No, it's hardware! 2023-11-30

   tags: amd, hardware/cpu, linux/kernel/ebpf, memory, observability/tracing, programming/python, programming/rust

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   • Xuanwo/when-i-find-rust-is-slow
   • Std::fs::read slow?
3. LWN - What every programmer should know about memory 2023-07-22

   tags: hardware, hardware/cpu, hardware/ram, memory, memory/cache, performance

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   • What every programmer should know about memory (Full PDF version) Mirror
   • Part 1: Introduction & Commodity Hardware Today
   • Part 2: CPU Caches
   • Part 3: Virtual Memory
   • Part 4: NUMA support
   • Part 5: What programmers can do
   • How much of ‘What Every Programmer Should Know About Memory’ is still valid?
4. Make your programs run faster by better using the data cache 2023-07-22

   tags: algorithm, data-structure, hardware/cpu, memory/cache, performance, programming/c, valgrind

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   • Use explicit data prefetching to faster process your data structure
   • ibogosavljevic/johnysswlab
   • What is cache memory - Gary explains
   • Cachegrind: a high-precision tracing profiler
5. SiliFuzz: Fuzzing CPUs by proxy 2022-09-11

   tags: google, hardware, hardware/cpu, programming/fuzzing

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   • https://raw.githubusercontent.com/google/silifuzz/main/paper/silifuzz.pdf
6. avx-turbo: Test the non-AVX, AVX2 and AVX-512 speeds across various active core counts 2019-12-31

   tags: hardware/cpu, instruction, intel, performance, performance/benchmark, processor

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   • https://en.wikipedia.org/wiki/Advanced_Vector_Extensions
   • https://www.intel.com/content/www/us/en/architecture-and-technology/avx-512-overview.html
7. c++ - Performance of built-in types : char vs short vs int vs. float vs. double - Stack Overflow 2019-12-31

   tags: hardware/cpu, memory, performance, processor, programming/c, programming/c++

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8. assembly - How to run a program without an operating system? - Stack Overflow 2019-04-26

   tags: bios, embedded, hack, hardware/cpu, operating-system, programming/assembly

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9. x86 Instructions | Twitter 2019-02-08

   tags: chip, hardware, hardware/cpu, processor, pun, twitter, wtf

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10. Playing Badass Acorn Archimedes Games on a Raspberry Pi | DXM Tech Support 2018-07-01

    tags: arm, computer, game, hardware/cpu, history, risc

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    • http://davetrott.co.uk/2017/03/strategy-is-sacrifice/
11. FlameScope: a visualization tool for exploring different time ranges as Flame Graphs. 2018-04-05

    tags: hardware/cpu, load, memory, observability/tracing, performance, stack, system

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    • https://medium.com/@NetflixTechBlog/netflix-flamescope-a57ca19d47bb
    • https://medium.com/netflix-techblog/java-in-flames-e763b3d32166
12. KCachegrind 2018-04-02

    tags: hardware/cpu, memory, memory/cache, performance, time, valgrind

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    • https://cgit.kde.org/kcachegrind.git/
    • https://github.com/KDE/kcachegrind (mirror)
    • http://nickology.com/2014/04/16/view-xdebug-cachegrind-files-on-mac-os/
    • https://stackoverflow.com/questions/33094913/how-do-i-read-the-ui-of-qcachegrind
13. htop - an interactive process viewer for Unix 2018-02-05

    tags: bsd, command-line, hardware/cpu, linux, load, memory, process, system, unix

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14. Exploiting modern microarchitectures: Meltdown, Spectre, and other attacks 2018-02-05

    tags: hack, hardware, hardware/cpu, meltdown, memory, security, spectre

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    • https://fosdem.org/2018/interviews/jon-masters/
    • https://fosdem.org/2018/schedule/event/closing_keynote/
15. Who was responsible for leaking the Meltdown/Spectre story beforehand, and thus breaking the co-ordinated patched release planned for 9th-Jan between various vendors? 2018-01-08

    tags: hack, hardware, hardware/cpu, intel, linux, memory, security

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    • https://cyber.wtf/2017/07/28/negative-result-reading-kernel-memory-from-user-mode/
    • https://cyber.wtf/2018/01/05/behind-the-scene-of-a-bug-collision/
    • https://lwn.net/Articles/738975/
    • https://lwn.net/Articles/741878/
    • https://lwn.net/Articles/741882/
    • https://twitter.com/misc0110/status/948706387491786752
    • https://www.theregister.co.uk/2018/01/02/intel_cpu_design_flaw/
16. Meltdown and Spectre 2018-01-04

    tags: amd, arm, attack, google, hack, hardware, hardware/cpu, intel, memory, research, security

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    • https://security.googleblog.com/2018/01/todays-cpu-vulnerability-what-you-need.html
    • https://googleprojectzero.blogspot.com/2018/01/reading-privileged-memory-with-side.html
    • https://www.reddit.com/r/linux/comments/7nybl1/meltdown_and_spectre/
    • https://www.reddit.com/r/linux/comments/7nzsih/intel_was_aware_of_the_chip_vulnerability_when/
    • https://www.reddit.com/r/linux/comments/7nyaku/todays_cpu_vulnerability_what_you_need_to_know/

    Exploits:

    • https://github.com/IAIK/meltdown
17. Heterogeneous memory management [LWN.net] 2017-09-26

    tags: gpu, hardware/cpu, linux, linux/kernel, memory

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    • https://www.phoronix.com/scan.php?page=search&q=Heterogeneous+Memory+Management
    • https://www.phoronix.com/scan.php?page=news_item&px=Nouveau-Compote
    • https://cgit.freedesktop.org/~glisse/compote/
    • https://www.infoworld.com/article/3196884/machine-learning/faster-machine-learning-is-coming-to-the-linux-kernel.html
18. Lenovo Thinkpad 13 + Linux - Feedback 2017-04-15

    tags: fan, hardware, hardware/cpu, heat, laptop, lenovo, linux, noise

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    +++: backlit keyboard, battery ++: HDPI matte screen, touchpad+trackpad -: BIOS messages in approximative English --: no ethernet port ---: cooling / fan noise

    ETH available through:

    • 10$ generic USB-C adapter
    • 25$ Lenovo USB-C adapter
    • 150$ Lenovo USB-C dock
    • 180$ Lenovo docking station

    Cooling / fan control:

    • triggered when the CPU reaches approx. 46° / 20% load
    • slowest speed: 3400 RPM (!), goes up to 4000+ RPM

    TODO:

    • try updating BIOS/UEFI
    • use a laptop cooling pad
    • killall -9 firefox # not really an option tho

    User-contributed feedback:

    • https://www.reddit.com/r/thinkpad/comments/4k2kzl/debian_on_the_thinkpad_13/
    • https://www.reddit.com/r/thinkpad/comments/4jh3wb/thinkpad_13_manjaroarch_impressions/
    • https://www.reddit.com/r/thinkpad/comments/4lzsks/my_thinkpad_13_experience_with_ubuntu_1604/
    • https://www.reddit.com/r/thinkpad/comments/4pieti/thinkpad_13_fan_vs_zenbook/
19. How to get information about graphics card (GPU) on Linux 2017-03-05

    tags: device, gpu, hardware/cpu, linux, system

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20. Proxmox VE Bug 839 – LXC containers show host /proc limits instead of actual limits available 2016-08-09

    tags: hardware/cpu, linux, linux/container, linux/container/lxc, observability, resource, virtualization/proxmox

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    via https://forum.proxmox.com/threads/lxc-container-show-load-and-hardware-from-host.26051/ rel https://github.com/lxc/lxcfs/issues/88