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Here's Why Radeon Graphics Are Faster On Linux 3.12

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  • #91
    AMD Phenom II now fine with "ondemand" governor even if Bulldozer is not

    Originally posted by Luke View Post
    On my FX8120, both Linux 3.11 and Linux 3.12 suffer a GPU performance hit when running the "ondemand" governor in Critter, the only non-CPU limited game I have.
    Earlier I posted my FX-8120 results showing that the difference between "performance" and "ondemand" governors has narrowed but is still significant. This evening I tested the results of the two governors on a Phenom II X4, a 955BE with a Radeon HD5570. Again the high-framerate, non CPU limited game "critter" was used, it can heat that little card all the way to 70C-and run at about 730fps peak on either governor setting.

    On that Phenom II, I found no discernable difference between leaving the governor in "ondemand" or putting it in "performance," no difference at all. Sometime I will have to see if that also applys to video edit rendering.

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    • #92
      Luke, while technically a graphically very simple GPU accelerated game might be well be non-CPU limited at the extreme, I'm not sure what you're trying to measure. It could well be you're hitting the GPU fillrate limit, exceeding the internal bandwidth of the card and at such high frame-rates I can't see how it's meaningful.

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      • #93
        To add my worthless opinion:

        Well, things do happen as they do. I never really wanted to speculate where it came from but had hoped that it would be the sum of changes in the free driver stack.
        Anyway.

        Michael probably used a really fast PC to limit bottlenecks from that side and to actually benchmark the GPU. But then it is of course wrong to use any non-performance governor (performance = which keeps the CPU untouched and at full speed).
        Still, for a real-world benchmark you just got to use ondemand since 99% of people will exactly use that one. Everything else would not make sense for all normal people. So at least that would be the effect most people would see. And it is good that a close look was done to find out what exactly caused it.

        So Michael you might learn from that and check with a full-speed-CPU governor again if something looks too strange. Or keep in mind any other possible larger influences on general performance. Still I think testing also on normal-world machines and normal configurations is a fair thing since most people do not have an i7+SSD+16 GB RAM or something combination.
        And please make these text boxes with the testing config larger.

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        • #94
          Originally posted by 89c51 View Post
          Average joe configuration should be used IMO. Also the user MUST NOT have to care about stuff like that. It should just work.
          Indeed, the OS should magically read average Joe's mind to determine what exactly he wants...

          /facepalm

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          • #95
            Originally posted by prodigy_ View Post
            Indeed, the OS should magically read average Joe's mind to determine what exactly he wants...

            /facepalm
            ...and apparently most of the settings in software are completely useless and should be eliminated. The default way or now way. Ever. No, not even in that one special case that would be important to _you_.
            Similar to the world of Gnome 3TM
            /sarcasm

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            • #96
              Originally posted by menfin87 View Post
              You are not interested as a driver developer ? So if a user complains about performance problems, do you just tell him "I don't see it so there is no problem" or do you maybe try to understand what is going on ? You should be glad that someone is testing an average user configuration to spot problems that would be blamed on you.
              If you set the governor to performance and send the benchmark results to me, I am interested. If you set the governor to the minimum CPU frequency, I am interested. If you set the governor to ondemand, I am not interested, because it would be a waste of time for me to try and reproduce your random results which might not be reproducible on my machine at all. In that case, you should probably be sending your results to the cpufreq team and not me.
              Last edited by marek; 10-16-2013, 07:31 AM.

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              • #97
                So the benchmarks that showed the improvements were with intel cpus: http://www.phoronix.com/scan.php?pag...12_major&num=2

                How come they even use ondemand? Has cpufreq not been superseded by pstate for several kernel versions now?

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                • #98
                  Ubuntu 13.10

                  It would be nice if Ubuntu can backport that commit in 13.10 (3.11 kernel).

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                  • #99
                    Originally posted by marek View Post
                    If you set the governor to performance and send the benchmark results to me, I am interested. If you set the governor to the minimum CPU frequency, I am interested. If you set the governor to ondemand, I am not interested, because it would be a waste of time for me to try and reproduce your random results which might not be reproducible on my machine at all. In that case, you should probably be sending your results to the cpufreq team and not me.
                    Perfectly fair request IMO. But, the underlying issue is the CPU should not have downclocked this much in the first place. I'm not saying this is the radeon driver's fault - I'm pretty certain this was an issue with cpufreq this entire time. In Windows or Mac, you don't have to mess with the governor (or whatever they call it) and their tests, to my knowledge, are not skewed. I understand why you don't want test results of ondemand, but the matter of the issue is that shouldn't be skewing the results in the first place. In other words, while disabling ondemand proves more reliable results, the tests should come out overall the same with ondemand enabled. I'm thinking kernel 3.12 is the first time the ondemand governor is working the way it SHOULD have.

                    On the other hand, as ChrisXY has mentioned, many of these governors are obsoleted anyway.

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                    • Originally posted by ChrisXY View Post
                      So the benchmarks that showed the improvements were with intel cpus: http://www.phoronix.com/scan.php?pag...12_major&num=2

                      How come they even use ondemand? Has cpufreq not been superseded by pstate for several kernel versions now?
                      On any OTHER distro (not *Buntu based) Yuuuuuuup. But Canonical hasn't gotten their heads out of their asses yet and switched yet. Someone said that it was because of bugs in the driver but im finding it hard to believe that THEY are hitting bugs that no one else has.

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