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A New BFS "Smoking" Scheduler For Linux 3.3

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  • #11
    Originally posted by RealNC View Post
    Yo, peace mah man. Me an' mah homies are chillin' an' readin' thah forums. Yo, check it out man, people are writin' "peace" cuz it makes 'em look cool.

    As for BFS, it's still better than CFS. I get XRUNS with JACK when running CFS that I do not get with BFS. So it's not a placebo, it's actually audible.

    Word. (/me crosses hands over my chest and makes the peace sign)
    I'm not sure you intended it, but this post sounds very racist to me. You're just making yourself look bad right now.

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    • #12
      Originally posted by smitty3268 View Post
      I agree that worst-case responsiveness is probably more important for desktop use than average or best-case, but anything that's multiple seconds has NOTHING to do with a CPU scheduler. Maybe the IO scheduler.
      It does seem to be related to IO, but I doubt it is the IO scheduler since it happens with cfq, deadline, and bfq.

      My OS is on an SSD, but I have a lot of HDDs with data on them. The most common correlation with the freezes is when I have a lot of IO going on with the HDDs (but not the OS SSD which is mostly idle) which are using mpt2sas. The freezes usually show up as all programs not responding for a few seconds (chromium, firefox, gnome-terminal, etc.).

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      • #13
        Originally posted by Paradox Uncreated View Post
        Freezes for a FEW SECONDS? Dude, I ran 0.33 ms latency, with renoise, browsing the internet in the background watching youtube. For quite a while. To see if occasional glitches would happen. They did not.
        Good for you. That does not mean that all workloads will have a max latency of 0.33ms.

        By the way, I thought the kernel timer could be set to 1000Hz at most, so I don't understand sub 1ms latencies.

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        • #14
          Originally posted by Paradox Uncreated View Post
          Most workloads will.
          Which is precisely the problem with your metric. Most is not all. Average is not worst case.

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          • #15
            Originally posted by jwilliams View Post
            Good for you. That does not mean that all workloads will have a max latency of 0.33ms.

            By the way, I thought the kernel timer could be set to 1000Hz at most, so I don't understand sub 1ms latencies.
            0.33ms doesn't make sense to begin with. You can configure JACK in a way that is says "0.33 ms". But that's just a calculation arising from the chosen FP, PB and sample rate you set in the settings. Just because the settings would want 0.33ms doesn't mean the kernel is gonna deliver.

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            • #16
              Originally posted by smitty3268 View Post
              I'm not sure you intended it, but this post sounds very racist to me. You're just making yourself look bad right now.
              It doesn't look racist to me. Just pretentious, which was the point.

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              • #17
                And how do you know you're getting 0.33ms? I can setup JACK for 0.167ms with BFS (16 FP, 192kHz, 2 P/B) and it works without a glitch. But it does not mean that this is the latency you actually get!

                (And this would be ridiculous anyway; 8ms is more than enough for any audio work.)

                Edit:
                You remind me of this guy: http://www.youtube.com/watch?v=foS84bEZSO4

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                • #18
                  Originally posted by Paradox Uncreated View Post
                  You obviously have an attiude problem RealNC. Ali G is you, not me.
                  Peace.

                  I doubt pursuing explaining 0.33 ms to you, is possible.
                  Well, not only to me; others also wonder what you mean with "0.33ms latency".

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                  • #19
                    Originally posted by Paradox Uncreated View Post
                    This is a kernelconfig for 0.33 ms latency. http://www.paradoxuncreated.com/tmp/.config39

                    Tested to work with intel dual-core, decent mobo, and firewire audio-card. Professional sound in other words.
                    And Nvidia gfx.. All the nice h/w one would want.
                    You've posted a config for a 2.6.39 generic kernel;

                    Code:
                    # Automatically generated make config: don't edit
                    # Linux/x86_64 2.6.39 Kernel Configuration
                    # Sat May 21 00:45:30 2011
                    This generic kernel would not perform as well as the same kernel using the BFS patch set (not on either of my Core2duo's, not on my AMD Phenom II 965 x4, and i doubt it would on my i7 ~ although that machine is newer, and i haven't/won't test it). 2.6.39 was just before linux-rt-3.0 came out. For the entire time between 2.6.33-rt and 3.0.1-rt -> i was using BFS kernels, as i had some hardware that didn't play nice with 2.6.33-rt - and subsequently ended up using BFS on all my systems, because it worked noticably betterthan CFS on the same kernel, during that period. On all machines (using 2.6.39, when it came out) BFS ran smoother / more stable & reliably for proaudio then CFS, and that's with using the 'threaded irq' boot parameter, that had been merged into mainline 2.6.39, from the -rt patches ... I tested this quite a bit at the time.

                    I currently use RT-kernels, but BFS is definitely a great alternative to CFS for certain workloads. I would likely be using it right now, if RT wasn't an option, or if I thought it was overkill for my usage.

                    To say, Con is wasting his time - as you've said before, is silly. Lots of people have been using BFS for years, in my own experiences, it was great and in situations where i was getting XRUNS with CFS (on any kernel 2.6.33+) - with BFS, they didn't exist (on several machines). I think both CFS and BFS have value, and it's healthy to have them both around.

                    my 2 cents
                    Last edited by ninez; 03-25-2012, 09:49 PM.

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                    • #20
                      Originally posted by Paradox Uncreated View Post
                      This is a kernelconfig for 0.33 ms latency. http://www.paradoxuncreated.com/tmp/.config39
                      # CONFIG_HZ_100 is not set
                      # CONFIG_HZ_250 is not set
                      # CONFIG_HZ_300 is not set
                      CONFIG_HZ_1000=y
                      CONFIG_HZ=1000

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