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Benchmarking The Ubuntu "Low-Jitter" Linux Kernel

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  • #61
    gamer2k completely misses both the point and the benchmark again, and states an old argument not relevant to this about "latency vs throughput". So if you increase latency on a c64, does it get more throughout? (*laugh here*)

    And indeed financial data, needs computation power and "throughput" aswell. Some pretty hardcore hardconvolution is often run on that aswell. Start multiplying that with 1000 stocks, and you need the kind of power, that Intel sees to be a market for this.

    Obviously some people think jitter is "disk-io". If you have reduced "disk-io" with there being the same disk i/o, you know jitter is lower. (lol)

    Indeed if jitter on a c64 was 20ms, very little sensible would happen on screen, reducing "throughput" in a ridicolous way.
    And ofcourse os-jitter blocks the usage of CPU, meaning the blocked amount of CPU goes up with cpu-cores. Imagine the loss on a 1000cpu computer.

    Peace Be With You.
    Last edited by Paradox Uncreated; 10-19-2012, 06:46 AM.

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    • #62
      I am wondering why you don't play games on your c64 then.

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      • #63
        Originally posted by Paradox Uncreated View Post
        I think I wrote most of the changes I did here: http://paradoxuncreated.com/Blog/wordpress/?p=2268
        I have not found any mention of the kernel config options you used. I can't even find them on the blog. Can you post them somewhere?

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        • #64
          Kano, I do, and you should try Mega Apocalypse to get an idea of how fun a low-jitter game can be. And then boot back in to high-level OS paradigms where there is latency, and get an idea of what I think of those.

          Originally posted by aceman View Post
          I have not found any mention of the kernel config options you used. I can't even find them on the blog. Can you post them somewhere?
          I post a lot there. Was there anything in specific? I can post the whole .config for 3.6.2 shaved local, which you can take inspiration from. PS, not full distro config.

          Peace Be With you.

          http://paradoxuncreated.com/tmp/_config3_6_2local
          (I also did some edits, but they are documented on the blog)

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          • #65
            Originally posted by Paradox Uncreated View Post
            I post a lot there. Was there anything in specific? I can post the whole .config for 3.6.2 shaved local, which you can take inspiration from. PS, not full distro config.

            http://paradoxuncreated.com/tmp/_config3_6_2local
            (I also did some edits, but they are documented on the blog)
            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.

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            • #66
              PS: http://en.wikipedia.org/wiki/TRON_Project

              Tron OS did realtime in 1984. Was forced off the market by MS.
              MS sees cp/m, copies it, although it is shit. Sells it to you.
              MS sees unix windowmanager, copies it, sells it to you as windows, now with extreme latency. The very other end of realtime you might say. (nontime? sleepingbag-time?)
              MS sees windowsblinds, copies it, another service on top of a poor scheduler and sells it to you.
              200 things in modern windows OS, can be turned off, leaving a BETTER computer. What are they doing being developed, and included in the price of the product sold to you?
              MS teaches obscure non-streamlined windows menus, and encourages people to not turn off these things, buying their whole corporate propaganda, and certifies people for this? What do you call that?

              Linux is open-source, and can be modified by anyone, patches are often made in days, and emails to developers read in minutes.
              By the time a fix may already be suggested on LKML, you have reached "I need to establish identiy please, I cannot hear you please" on MS support, phone to another country.

              And that is ofcourse just some of it.

              And then MS lanches it`s own OS, as a cure for headaches in their current (they did this with 98)

              It`s mad, and serves no human.

              Peace Be With You.

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              • #67
                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

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                • #68
                  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.

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                  • #69
                    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

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                    • #70
                      Here, predicting trends in 1966, http://www.drdobbs.com/if-you-cant-s...t-of/184404040

                      Nodoubt without "os-jitter".

                      Peace Be With You.

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                      • #71
                        The worlds first lamer: Mrs. Sutherland was heard to ask: "Will it replace me?"

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                        • #72
                          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.

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                          • #73
                            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.

                            Comment


                            • #74
                              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.

                              Comment


                              • #75
                                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).

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