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Linux's "Ondemand" Governor Is No Longer Fit

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  • #21
    Originally posted by Ericg View Post
    Hey Rahul, can you clarify something for me... just how often is the CPU -really- idling on (for example) the Fedora default desktop setup? I get the Race To Idle, I just don't see when the system would ever be able to fully IDLE because of all the daemons and everything thats going on in the background. If you've got things like KDE's nepomuk constantly scanning for changed files (or dropbox / google drive doing the same thing on non-KDE systems), or any kind of server running on the system, dont those things keep the system busy 24/7?
    No, they listen for file-system changes. Unless you change a file, the file indexer/syncer will not reindex it.

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    • #22
      Just updated to kernel 3.9 on my Ivy Bridge laptop to see if it makes a difference. It's hard to say non-subjectively without being lazy and doing some real objective testing, which I didn't, but it seems to have made a difference in both battery life, cpu temperatures, and hence fan noise when doing various tasks.

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      • #23
        Originally posted by carewolf View Post
        No, they listen for file-system changes. Unless you change a file, the file indexer/syncer will not reindex it.
        Correct, there is a kernel API which does that, so userspace can go to sleep and just get notified by the filesystem.

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        • #24
          Originally posted by molecule-eye View Post
          Just updated to kernel 3.9 on my Ivy Bridge laptop to see if it makes a difference. It's hard to say non-subjectively without being lazy and doing some real objective testing, which I didn't, but it seems to have made a difference in both battery life, cpu temperatures, and hence fan noise when doing various tasks.
          What does /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor say for you?
          I thought that Ivy Bridge is not yet supported?

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          • #25
            Originally posted by user82 View Post
            What does /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor say for you?
            I thought that Ivy Bridge is not yet supported?
            Look at #17.

            My mobile ivy bridge:
            Code:
             $ cpupower frequency-info
            analyzing CPU 0:
              driver: intel_pstate
              CPUs which run at the same hardware frequency: 0
              CPUs which need to have their frequency coordinated by software: 0
              maximum transition latency: 0.97 ms.
              hardware limits: 1.20 GHz - 3.20 GHz
              available cpufreq governors: performance, powersave
              current policy: frequency should be within 1.20 GHz and 3.20 GHz.
                              The governor "performance" may decide which speed to use
                              within this range.
              boost state support:
                Supported: yes
                Active: yes
                25500 MHz max turbo 4 active cores
                25500 MHz max turbo 3 active cores
                25500 MHz max turbo 2 active cores
                25500 MHz max turbo 1 active cores

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            • #26
              Originally posted by user82 View Post
              What does /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor say for you?
              I thought that Ivy Bridge is not yet supported?
              Only if patched.

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              • #27
                Originally posted by Ericg View Post
                No, OnDemand is still fine for AMD because its AMD. But this is about creating a driver that ACTUALLY does a good job (not a half--assed) job of managing the CPU in terms of power management / performance. Once AMD writes a new scaling driver, like Intel did for intel_pstate, you should switch to that.

                TL;DR: OnDemand is a half assed solution, new pstate drivers are the right solution. Intel only so far. AMD has to write their own.
                Do you think that they will actually submit such code with them shutting down their OSRC and laying off their developers responsible for their cpufrq/PowerNow developers?

                http://www.phoronix.com/scan.php?pag...tem&px=MTIyMDQ

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                • #28
                  Originally posted by deanjo View Post
                  Do you think that they will actually submit such code with them shutting down their OSRC and laying off their developers responsible for their cpufrq/PowerNow developers?

                  http://www.phoronix.com/scan.php?pag...tem&px=MTIyMDQ
                  I don't THINK AMD is gonna be in business within the next 5 years. And while I realize that does not exactly answer your question, in a way it does.

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                  • #29
                    Originally posted by Ericg View Post
                    I don't THINK AMD is gonna be in business within the next 5 years. And while I realize that does not exactly answer your question, in a way it does.
                    Not possible. Even though AMD hardware is really unspectacular they beat Intel hands down in the performance-cost ratio. Intel can play the price game, but if they drop their prices to the level of AMD's there will most certainly be some silly lawsuit being filed on the grounds of the most heavily abused word in the industry: anti-competition. (or dumping, whatever).

                    Not to mention AMD has some presence in the dedicated GPU market. Although the alleged performance of Haswell's onboard graphics core are destroying that presence...

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                    • #30
                      Originally posted by Sonadow View Post
                      Not possible. Even though AMD hardware is really unspectacular they beat Intel hands down in the performance-cost ratio. Intel can play the price game, but if they drop their prices to the level of AMD's there will most certainly be some silly lawsuit being filed on the grounds of the most heavily abused word in the industry: anti-competition. (or dumping, whatever).

                      Not to mention AMD has some presence in the dedicated GPU market. Although the alleged performance of Haswell's onboard graphics core are destroying that presence...
                      Are they -really- beating Intel on the value end of the spectrum though? Core i5 Haswell is gonna have MORE than adequate graphics for anything up to gaming (and even some gaming) great CPU performance, power consumption is going to be at near-ARM levels, all for about $200 I'm guessing, maybe less. AMD's graphics may be better, but they are still reeling from the clusterfsck known as Bulldozer, their power consumption is up, they cant even idle at the levels that Intel can, and their chips cost between $100 and $200 for Piledriver.

                      Quite honestly, at least for me, I wont even CONSIDER an AMD APU for a Laptop just because of the heat and power consumption. Desktop, okay, maybe they have a shot in one of my builds just because power consumption doesnt matter as much there.

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