6 ms·

There's likely a data bubble or dependency in the CPU pipeline that needs an extra few picoseconds to fetch the correct data.

by hgdsraj 10y ago

zapu 10y ago
I think this is for Makefiles...
- kibwen 10y ago
  Ugh, they were right, Rust's syntax really is garbage. :P
  - Retr0spectrum 10y ago
    What do you mean? Makefiles are not written in rust...
    - kibwen 10y ago
      Just making a joke, my friend. :)
      - bcook 10y ago
        Use /s or include a pic of your sarcastic facial expression next time...
        spdionis 10y ago
        Luckily we can't include pics
        lisivka 10y ago
        We can, using data: protocol. Copy following text to URL field: data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" id="Layer_1" x="0px" y="0px" viewBox="0 0 100 100" enable-background="new 0 0 100 100" xml:space="preserve" height="100px" width="100px"><g><path d="M28.1,36.6c4.6,1.9,12.2,1.6,20.9,1.1c8.9-0.4,19-0.9,28.9,0.9c6.3,1.2,11.9,3.1,16.8,6c-1.5-12.2-7.9-23.7-18.6-31.3 c-4.9-0.2-9.9,0.3-14.8,1.4C47.8,17.9,36.2,25.6,28.1,36.6z"/><path d="M70.3,9.8C57.5,3.4,42.8,3.6,30.5,9.5c-3,6-8.4,19.6-5.3,24.9c8.6-11.7,20.9-19.8,35.2-23.1C63.7,10.5,67,10,70.3,9.8z"/><path d="M16.5,51.3c0.6-1.7,1.2-3.4,2-5.1c-3.8-3.4-7.5-7-11-10.8c-2.1,6.1-2.8,12.5-2.3,18.7C9.6,51.1,13.4,50.2,16.5,51.3z"/><path d="M9,31.6c3.5,3.9,7.2,7.6,11.1,11.1c0.8-1.6,1.7-3.1,2.6-4.6c0.1-0.2,0.3-0.4,0.4-0.6c-2.9-3.3-3.1-9.2-0.6-17.6 c0.8-2.7,1.8-5.3,2.7-7.4c-5.2,3.4-9.8,8-13.3,13.7C10.8,27.9,9.8,29.7,9,31.6z"/><path d="M15.4,54.7c-2.6-1-6.1,0.7-9.7,3.4c1.2,6.6,3.9,13,8,18.5C13,69.3,13.5,61.8,15.4,54.7z"/><path d="M39.8,57.6C54.3,66.7,70,73,86.5,76.4c0.6-0.8,1.1-1.6,1.7-2.5c4.8-7.7,7-16.3,6.8-24.8c-13.8-9.3-31.3-8.4-45.8-7.7 c-9.5,0.5-17.8,0.9-23.2-1.7c-0.1,0.1-0.2,0.3-0.3,0.4c-1,1.7-2,3.4-2.9,5.1C28.2,49.7,33.8,53.9,39.8,57.6z"/><path d="M26.2,88.2c3.3,2,6.7,3.6,10.2,4.7c-3.5-6.2-6.3-12.6-8.8-18.5c-3.1-7.2-5.8-13.5-9-17.2c-1.9,8-2,16.4-0.3,24.7 C20.6,84.2,23.2,86.3,26.2,88.2z"/><path d="M30.9,73c2.9,6.8,6.1,14.4,10.5,21.2c15.6,3,32-2.3,42.6-14.6C67.7,76,52.2,69.6,37.9,60.7C32,57,26.5,53,21.3,48.6 c-0.6,1.5-1.2,3-1.7,4.6C24.1,57.1,27.3,64.5,30.9,73z"/></g></svg>
        brokenmachine 10y ago
        Seems like a lot of effort to get a sarcastic emoticon. :-P
        whitten 10y ago
        For curiosity, what browser does this work in? I tried it in Internet Explorer 11 and got no results.
        lisivka 10y ago
        Firefox, Chrome.
        kibwen 10y ago
        I'm actually working on a browser extension that will use natural language recognition to detect when you're typing a sarcastic comment and automatically take a photo with your webcam and upload it to imgur. :) (/s)
WildUtah 10y ago
When new faster CPUs appear, they add more nops.
- kibwen 10y ago
  Per Moore's law, the number of nops must double every 18 months. For codebases originally written in 1977, the year of make's origin, this now measures in the dozens of meganops.
  - Retr0spectrum 10y ago
    To be extra pedantic, Moore's law says nothing about clock speed.
    - reitzensteinm 10y ago
      To be extra, extra pedantic, clock speed is not the only factor. You must also take in to account the number of NOPs executed per cycle (NPC). Indeed, chip architects would struggle to find a way to execute vast quantities of NOPs efficiently until the release of the Itanium in 2001.
      - __jal 10y ago
        Don't forget the infamous NOP bug that made all the headlines in the late 90s, when certain values of NOP would actually do something.
  - throwanem 10y ago
    How apropos! "Dozens of meganops" was my instant reaction to the linked makefile, too.
  - DonHopkins 10y ago
    Now you can execute billions of peta-nops in parallel using GPU hardware acceleration in the cloud.
shawnz 10y ago
What is a "data bubble"? How would what you're describing not be a hardware bug?
- danaliv 10y ago
  See https://en.wikipedia.org/wiki/Bubble_(computing) https://en.wikipedia.org/wiki/Bubble_(computing). It's not a bug; it's a side effect of how pipelining works. (But obviously this has nothing to do with the link, since it's a Makefile, not assembly.)
- throwanem 10y ago
  > What is a "data bubble"? A common result of moving instructions through early processors at too high a rate to maintain laminar flow. Early cryptographic algorithms in particular were severely limited by such considerations, until the advent of modern pipelining algorithms vastly reduced susceptibility to data cavitation. As a point of historical interest, the "dataflow" paradigm in programming originated as an alternative approach to solving this problem, which attempted to avoid it entirely by having everything happen at once all over the place through magic. Between the misnomer and the heavy drain on the limited market for wizard labor, it's easy to see why the paradigm, though intriguing and not without useful lessons, failed to gain meaningful traction in the industry - perhaps ironically, there was just too much friction for it ever really to take off.

There's likely a data bubble or dependency in the CPU pipeline that needs an extra few picoseconds to fetch the correct data.

by hgdsraj 10y ago

There's likely a data bubble or dependency in the CPU pipeline that needs an extra few picoseconds to fetch the correct data.

zapu 10y ago

I think this is for Makefiles...

kibwen 10y ago
Ugh, they were right, Rust's syntax really is garbage. :P
- Retr0spectrum 10y ago
  What do you mean? Makefiles are not written in rust...
  - kibwen 10y ago
    Just making a joke, my friend. :)
    - bcook 10y ago
      Use /s or include a pic of your sarcastic facial expression next time...
      - spdionis 10y ago
        Luckily we can't include pics
        lisivka 10y ago
        We can, using data: protocol. Copy following text to URL field: data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" id="Layer_1" x="0px" y="0px" viewBox="0 0 100 100" enable-background="new 0 0 100 100" xml:space="preserve" height="100px" width="100px"><g><path d="M28.1,36.6c4.6,1.9,12.2,1.6,20.9,1.1c8.9-0.4,19-0.9,28.9,0.9c6.3,1.2,11.9,3.1,16.8,6c-1.5-12.2-7.9-23.7-18.6-31.3 c-4.9-0.2-9.9,0.3-14.8,1.4C47.8,17.9,36.2,25.6,28.1,36.6z"/><path d="M70.3,9.8C57.5,3.4,42.8,3.6,30.5,9.5c-3,6-8.4,19.6-5.3,24.9c8.6-11.7,20.9-19.8,35.2-23.1C63.7,10.5,67,10,70.3,9.8z"/><path d="M16.5,51.3c0.6-1.7,1.2-3.4,2-5.1c-3.8-3.4-7.5-7-11-10.8c-2.1,6.1-2.8,12.5-2.3,18.7C9.6,51.1,13.4,50.2,16.5,51.3z"/><path d="M9,31.6c3.5,3.9,7.2,7.6,11.1,11.1c0.8-1.6,1.7-3.1,2.6-4.6c0.1-0.2,0.3-0.4,0.4-0.6c-2.9-3.3-3.1-9.2-0.6-17.6 c0.8-2.7,1.8-5.3,2.7-7.4c-5.2,3.4-9.8,8-13.3,13.7C10.8,27.9,9.8,29.7,9,31.6z"/><path d="M15.4,54.7c-2.6-1-6.1,0.7-9.7,3.4c1.2,6.6,3.9,13,8,18.5C13,69.3,13.5,61.8,15.4,54.7z"/><path d="M39.8,57.6C54.3,66.7,70,73,86.5,76.4c0.6-0.8,1.1-1.6,1.7-2.5c4.8-7.7,7-16.3,6.8-24.8c-13.8-9.3-31.3-8.4-45.8-7.7 c-9.5,0.5-17.8,0.9-23.2-1.7c-0.1,0.1-0.2,0.3-0.3,0.4c-1,1.7-2,3.4-2.9,5.1C28.2,49.7,33.8,53.9,39.8,57.6z"/><path d="M26.2,88.2c3.3,2,6.7,3.6,10.2,4.7c-3.5-6.2-6.3-12.6-8.8-18.5c-3.1-7.2-5.8-13.5-9-17.2c-1.9,8-2,16.4-0.3,24.7 C20.6,84.2,23.2,86.3,26.2,88.2z"/><path d="M30.9,73c2.9,6.8,6.1,14.4,10.5,21.2c15.6,3,32-2.3,42.6-14.6C67.7,76,52.2,69.6,37.9,60.7C32,57,26.5,53,21.3,48.6 c-0.6,1.5-1.2,3-1.7,4.6C24.1,57.1,27.3,64.5,30.9,73z"/></g></svg>
        brokenmachine 10y ago
        Seems like a lot of effort to get a sarcastic emoticon. :-P
        whitten 10y ago
        For curiosity, what browser does this work in? I tried it in Internet Explorer 11 and got no results.
        lisivka 10y ago
        Firefox, Chrome.
      - kibwen 10y ago
        I'm actually working on a browser extension that will use natural language recognition to detect when you're typing a sarcastic comment and automatically take a photo with your webcam and upload it to imgur. :) (/s)

WildUtah 10y ago

When new faster CPUs appear, they add more nops.

kibwen 10y ago
Per Moore's law, the number of nops must double every 18 months. For codebases originally written in 1977, the year of make's origin, this now measures in the dozens of meganops.
- Retr0spectrum 10y ago
  To be extra pedantic, Moore's law says nothing about clock speed.
  - reitzensteinm 10y ago
    To be extra, extra pedantic, clock speed is not the only factor. You must also take in to account the number of NOPs executed per cycle (NPC). Indeed, chip architects would struggle to find a way to execute vast quantities of NOPs efficiently until the release of the Itanium in 2001.
    - __jal 10y ago
      Don't forget the infamous NOP bug that made all the headlines in the late 90s, when certain values of NOP would actually do something.
- throwanem 10y ago
  How apropos! "Dozens of meganops" was my instant reaction to the linked makefile, too.
- DonHopkins 10y ago
  Now you can execute billions of peta-nops in parallel using GPU hardware acceleration in the cloud.

shawnz 10y ago

What is a "data bubble"? How would what you're describing not be a hardware bug?

danaliv 10y ago
See https://en.wikipedia.org/wiki/Bubble_(computing) https://en.wikipedia.org/wiki/Bubble_(computing). It's not a bug; it's a side effect of how pipelining works. (But obviously this has nothing to do with the link, since it's a Makefile, not assembly.)
throwanem 10y ago
> What is a "data bubble"? A common result of moving instructions through early processors at too high a rate to maintain laminar flow. Early cryptographic algorithms in particular were severely limited by such considerations, until the advent of modern pipelining algorithms vastly reduced susceptibility to data cavitation. As a point of historical interest, the "dataflow" paradigm in programming originated as an alternative approach to solving this problem, which attempted to avoid it entirely by having everything happen at once all over the place through magic. Between the misnomer and the heavy drain on the limited market for wizard labor, it's easy to see why the paradigm, though intriguing and not without useful lessons, failed to gain meaningful traction in the industry - perhaps ironically, there was just too much friction for it ever really to take off.