Announcement

Collapse
No announcement yet.

Benchmarking The Ubuntu "Low-Jitter" Linux Kernel

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • JanC
    replied
    Originally posted by unix_epoch View Post
    (...)
    Throughput benchmarks should only be included as an afterthought, if at all. They don't measure the important variable.
    Throughput benchmarking is important too, but mostly to make sure that after confirming that the changes give you low jitter, it doesn't impact throughput too much. You don't want nearly no jitter @ 1 FPS...

    (It's like after finding a new medicine, you want to make sure it doesn't have too many side-effects.)
    Last edited by JanC; 10-20-2012, 02:47 PM.

    Leave a comment:


  • JanC
    replied
    Originally posted by Paradox Uncreated View Post
    PS: Even games were made in basic on c64, that had no slowdowns. Imagine interpreted basic, on a 1mhz CPU, can do lower-jitter than a modern pc. (well on many PCs )
    The OS on the C64 didn't support multitasking, so there weren't other processes competing for CPU time. That allows the application/game developer to have complete control over the CPU usage.

    The same was mostly true on a PC with DOS (see all the amazing things people from the demoscene did on that platform).

    Leave a comment:


  • JanC
    replied
    Originally posted by YoungManKlaus View Post
    Noob. Beer is very good at preserving itself without any additives and refridgeration, which is exactly why it is not kept in a freezer in the super market. I know because I tried one - even a unfiltered one where the guaranteed time is shorter, but still in the range of months - about two years after that date and it was still good as ever.
    Prerequisites:
    - bottled in glass bottle, not aluminium can (though that should also work), or worst: PET
    - not opened
    - preferably strong (the stronger the better, obviously, as less germs survive)
    - brewer has to know what he was doing

    ... so in short, US beer is out
    The oldest beer I drank was > 20 years old. And it was unpasteurised & unfiltered (a flemish "oud bruin"). It was a little "flat" tasting after so much time, but still tasted okay, and I didn't get sick...

    And the "Abt" trappist ale from West-Vleteren is often at its best at 6-8yo (bottle refermentation and an artisanal brewing process make the result slightly unpredictable, but it's very unlikely it will be bad after 8 years).

    Leave a comment:


  • Paradox Ethereal
    replied
    Originally posted by aceman View Post
    Thanks at least for this full config.
    Some list of the specific options you think must be set would be nice, e.g. a diff to the distro config.
    Also, I wonder where do you get the CONFIG_HZ_90 option, when vanilla kernel has a 100Hz option. Also I wonder why the lowest value is best, when the kernel config says the highest (1000Hz) option is for low-latency.
    You can edit Kconfig.hz, in kernels, kernel directory. When I am done tweaking, and feel I have sufficently tried and gathered all information on this, I will do some patches.

    A lot of people do believe 1000hz is the best, and I was recently told to use 10.000hz and BFS for "lowest latency". This is not true at all, infact a setting of 20hz with BFS, will not be noticably different from 10.000 except cpu-usage. With CFS though, 90hz gives the least jitter. Also the value may not scale, as the kernel code says the scaling is a bit unpredictable. It gives the lowest jitter on my dualcore though. I would strongly advise against 1000hz on the desktop, even though many believe that to be the best.

    Peace Be With You.

    Leave a comment:


  • Paradox Ethereal
    replied
    Originally posted by ext73 View Post
    My kernels are faster and more responsive ... and energy consumption + my script APM at most 40-60% of standard solutions

    http://ubuntu.pl/forum/viewforum.php?f=216

    https://www.youtube.com/watch?v=JDav...1&feature=plcp

    https://www.youtube.com/watch?v=eWqP...2&feature=plcp

    http://dl.dropbox.com/u/72313101/kub...M-redehead.png

    greetings

    e X t 7 3
    If you have anything to contribute to the os-jitter discussion, please do. However jitter seems often to be compromised by wattage.

    Peace Be With You.

    Leave a comment:


  • Paradox Ethereal
    replied
    Imagine if you could use a million z80s. 1ms osjitter, and suddently a million ms lost. Well figuratively speaking. One needs to have a good multicpu mainboard design aswell. But still. That is what liked about BeOS in it`s day. Designed from the ground of for multiple cpus. Instead of 1 or 2 expensive cpus, 8 cheap. Give the ghetto people doom 3.

    As many obscure things, good or bad, it faded.

    Leave a comment:


  • Paradox Ethereal
    replied
    edit: outdated
    Last edited by Paradox Ethereal; 10-27-2017, 06:22 PM.

    Leave a comment:


  • Paradox Ethereal
    replied
    Here, predicting trends in 1966, http://www.drdobbs.com/if-you-cant-s...t-of/184404040

    Nodoubt without "os-jitter".

    Peace Be With You.

    Leave a comment:


  • Paradox Ethereal
    replied
    And what is this? Do you need to be a rocketscientist to understand this?

    http://www.hq.nasa.gov/pao/History/c...pendix-II.html

    Leave a comment:


  • Paradox Ethereal
    replied
    Think about that MS, caused a latency in innovation the size of 30 years. Now ofcourse modern OSs are resembling real-time more and more. You could have had that in 1984. That is what agressive profit-philosphies get you.

    Peace Be With You.

    Leave a comment:

Working...
X