Re: 2.6.17-rc3: cpufreq-set -g ondemand does not work
On Wed, May 17, 2006 at 11:09:21PM +1000, Paul Collins wrote: Bernhard Reiter [EMAIL PROTECTED] writes: but my idea would be that an ondemand govenor would just work on a load average with some delay to even out spikes. The userspace governor combined with powernowd will give you this. And since the userspace governor defaults to the lowest CPU frequency, it all works out nicely. I've using it happily on my PowerBook. Yes I will try powernowd it sounds nice and it is good to know that it works well for people with powerbooks. My point was that I would expect that the kernel itself comes with a simplistic governor doing this. pgpWRpxNz1eeN.pgp Description: PGP signature
Re: 2.6.17-rc3: cpufreq-set -g ondemand does not work
speeds? The code path on the 7447A models appears to have a settle delay of 1 ms after the feature call (which boils down to an OUTB, basically), another 0.1 ms after the low_choose_7447a_dfs call which shouldn't take very long either. Am I missing something, Ben? I'm being over conservative bcs of the voltage change That's the 1 ms, after which the speed switch happens. Do you think the voltage switch actually takes longer to settle than this? I'd not be surprised if the latency was as low as 2 ms total - can we profile this reliably in some way? I guess I'll just set the latency to 5 ms and see what happens ... Last time I looked the on-demand governor was using a workqueue... anything that has a latency of more than a few dozen usec in a workqueue shall be shot... That may be right - it's probably the reason for the latency cutoff at 10 ms. People might not be impressed if they try ondemand switching :-) Anyway: is it safe to try, or will I fry my system board? Michael -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: 2.6.17-rc3: cpufreq-set -g ondemand does not work
Ben, Michael,
On Wed, May 17, 2006 at 08:15:42AM +1000, Benjamin Herrenschmidt wrote:
On Tue, 2006-05-16 at 14:54 +0200, Michael Schmitz wrote:
JoseJX write there that ondemand and conservative cannot be used
on 7xx/74xx processors because of the time required to switch speeds.
The reason seems to be a rather conservative assumption on the latency
('probably takes forever') - does it really take more than 10 ms to switch
speeds? The code path on the 7447A models appears to have a settle delay
of 1 ms after the feature call (which boils down to an OUTB, basically),
another 0.1 ms after the low_choose_7447a_dfs call which shouldn't take
very long either. Am I missing something, Ben?
I'm being over conservative bcs of the voltage change
I'd not be surprised if the latency was as low as 2 ms total - can we
profile this reliably in some way? I guess I'll just set the latency to 5
ms and see what happens ...
Last time I looked the on-demand governor was using a workqueue...
anything that has a latency of more than a few dozen usec in a workqueue
shall be shot...
you are talking over my head here,
but my idea would be that an ondemand govenor would just work
on a load average with some delay to even out spikes.
Why not raise that delay and have no problem?
I my simplistic world I would expect the kernel to have such an option
as this is very close to the core. If the user wants more sofisticated
algorithms, this is very real user space daemons come in.
Am I completey off the mark here?
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Re: 2.6.17-rc3: cpufreq-set -g ondemand does not work
On Wed, 2006-05-17 at 10:45 +0200, Michael Schmitz wrote: speeds? The code path on the 7447A models appears to have a settle delay of 1 ms after the feature call (which boils down to an OUTB, basically), another 0.1 ms after the low_choose_7447a_dfs call which shouldn't take very long either. Am I missing something, Ben? I'm being over conservative bcs of the voltage change That's the 1 ms, after which the speed switch happens. Do you think the voltage switch actually takes longer to settle than this? I don't have proper specs, it seems to depend on the machine. I'd rather avoid playing wave generator with the voltage control chip though :) That may be right - it's probably the reason for the latency cutoff at 10 ms. People might not be impressed if they try ondemand switching :-) Anyway: is it safe to try, or will I fry my system board? I suppose at worse you'll lockup randomly but I can't promise :) Ben. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: 2.6.17-rc3: cpufreq-set -g ondemand does not work
Bernhard Reiter [EMAIL PROTECTED] writes: but my idea would be that an ondemand govenor would just work on a load average with some delay to even out spikes. The userspace governor combined with powernowd will give you this. And since the userspace governor defaults to the lowest CPU frequency, it all works out nicely. I've using it happily on my PowerBook. -- Dag vijandelijk luchtschip de huismeester is dood -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
Re: 2.6.17-rc3: cpufreq-set -g ondemand does not work
On Mon, May 15, 2006 at 07:27:42PM +0200, Bin Zhang wrote: On 5/8/06, Bernhard Reiter [EMAIL PROTECTED] wrote: cpufreq-set -g ondemand fails on linux-2.6.17-rc3 PowerBook5,6, config see below. dmesg has: ondemand governor failed to load due to too long transition latency same with conservative. Both modules are loaded as lsmod shows. I will probably try to change the .config to make ondemand or conservative the default, but this might be a bug nevertheless, thus I am reporting. Any hints? Maybe this helps: http://forums.gentoo.org/viewtopic-t-462417.html Yes, it does. JoseJX write there that ondemand and conservative cannot be used on 7xx/74xx processors because of the time required to switch speeds. Powernowd is recommended. This explains it. I guess the description or dependencies of those modules could be improved so it is more clear that they are not useful to me. Bernhard pgpBBdbcpi2Qv.pgp Description: PGP signature
Re: 2.6.17-rc3: cpufreq-set -g ondemand does not work
Maybe this helps:
http://forums.gentoo.org/viewtopic-t-462417.html
Yes, it does.
JoseJX write there that ondemand and conservative cannot be used
on 7xx/74xx processors because of the time required to switch speeds.
The reason seems to be a rather conservative assumption on the latency
('probably takes forever') - does it really take more than 10 ms to switch
speeds? The code path on the 7447A models appears to have a settle delay
of 1 ms after the feature call (which boils down to an OUTB, basically),
another 0.1 ms after the low_choose_7447a_dfs call which shouldn't take
very long either. Am I missing something, Ben?
I'd not be surprised if the latency was as low as 2 ms total - can we
profile this reliably in some way? I guess I'll just set the latency to 5
ms and see what happens ...
Powernowd is recommended.
Indeed.
Michael
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Re: 2.6.17-rc3: cpufreq-set -g ondemand does not work
On Tue, 2006-05-16 at 14:54 +0200, Michael Schmitz wrote:
Maybe this helps:
http://forums.gentoo.org/viewtopic-t-462417.html
Yes, it does.
JoseJX write there that ondemand and conservative cannot be used
on 7xx/74xx processors because of the time required to switch speeds.
The reason seems to be a rather conservative assumption on the latency
('probably takes forever') - does it really take more than 10 ms to switch
speeds? The code path on the 7447A models appears to have a settle delay
of 1 ms after the feature call (which boils down to an OUTB, basically),
another 0.1 ms after the low_choose_7447a_dfs call which shouldn't take
very long either. Am I missing something, Ben?
I'm being over conservative bcs of the voltage change
I'd not be surprised if the latency was as low as 2 ms total - can we
profile this reliably in some way? I guess I'll just set the latency to 5
ms and see what happens ...
Last time I looked the on-demand governor was using a workqueue...
anything that has a latency of more than a few dozen usec in a workqueue
shall be shot...
Ben
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Re: 2.6.17-rc3: cpufreq-set -g ondemand does not work
On Mon, May 08, 2006 at 03:07:50PM +0200, Bernhard Reiter wrote: cpufreq-set -g ondemand fails on linux-2.6.17-rc3 PowerBook5,6, config see below. dmesg has: ondemand governor failed to load due to too long transition latency Nobody saw this. It is all working for you? Are people using the ondemand or conservative user land governor? same with conservative. Both modules are loaded as lsmod shows. I will probably try to change the .config to make ondemand or conservative the default, but this might be a bug nevertheless, thus I am reporting. Any hints? Relevant .config: CONFIG_CPU_FREQ=y CONFIG_CPU_FREQ_TABLE=y CONFIG_CPU_FREQ_DEBUG=y CONFIG_CPU_FREQ_STAT=y CONFIG_CPU_FREQ_STAT_DETAILS=y # CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE is not set CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE=y CONFIG_CPU_FREQ_GOV_PERFORMANCE=m CONFIG_CPU_FREQ_GOV_POWERSAVE=m CONFIG_CPU_FREQ_GOV_USERSPACE=y CONFIG_CPU_FREQ_GOV_ONDEMAND=m CONFIG_CPU_FREQ_GOV_CONSERVATIVE=m CONFIG_CPU_FREQ_PMAC=y # CONFIG_PPC601_SYNC_FIX is not set -- Professional Service for Free Software (intevation.net) The FreeGIS Project (freegis.org) FSFE(fsfeurope.org) pgp40zoAuwCVa.pgp Description: PGP signature
Re: 2.6.17-rc3: cpufreq-set -g ondemand does not work
On 5/8/06, Bernhard Reiter [EMAIL PROTECTED] wrote: cpufreq-set -g ondemand fails on linux-2.6.17-rc3 PowerBook5,6, config see below. dmesg has: ondemand governor failed to load due to too long transition latency same with conservative. Both modules are loaded as lsmod shows. I will probably try to change the .config to make ondemand or conservative the default, but this might be a bug nevertheless, thus I am reporting. Any hints? Maybe this helps: http://forums.gentoo.org/viewtopic-t-462417.html Best regards, Bin Relevant .config: CONFIG_CPU_FREQ=y CONFIG_CPU_FREQ_TABLE=y CONFIG_CPU_FREQ_DEBUG=y CONFIG_CPU_FREQ_STAT=y CONFIG_CPU_FREQ_STAT_DETAILS=y # CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE is not set CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE=y CONFIG_CPU_FREQ_GOV_PERFORMANCE=m CONFIG_CPU_FREQ_GOV_POWERSAVE=m CONFIG_CPU_FREQ_GOV_USERSPACE=y CONFIG_CPU_FREQ_GOV_ONDEMAND=m CONFIG_CPU_FREQ_GOV_CONSERVATIVE=m CONFIG_CPU_FREQ_PMAC=y # CONFIG_PPC601_SYNC_FIX is not set
Re: 2.6.17-rc3: cpufreq-set -g ondemand does not work
On Mon, 2006-05-15 at 19:16 +0200, Bernhard Reiter wrote: On Mon, May 08, 2006 at 03:07:50PM +0200, Bernhard Reiter wrote: cpufreq-set -g ondemand fails on linux-2.6.17-rc3 PowerBook5,6, config see below. dmesg has: ondemand governor failed to load due to too long transition latency [EMAIL PROTECTED]: sudo cpufreq-set -g ondemand [~] Error setting new values. Common errors: - Do you have proper administration rights? (super-user?) - Is the governor you requested available and modprobed? - Trying to set an invalid policy? - Trying to set a specific frequency, but userspace governor is not available, for example because of hardware which cannot be set to a specific frequency or because the userspace governor isn't loaded? [EMAIL PROTECTED]: dmesg | tail -1 [~] ondemand governor failed to load due to too long transition latency [EMAIL PROTECTED]: grep demand /boot/config-2.6.17-rc2 [~] CONFIG_CPU_FREQ_GOV_ONDEMAND=y [EMAIL PROTECTED]: cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors conservative ondemand powersave userspace performance Nobody saw this. It is all working for you? Are people using the ondemand or conservative user land governor? -- Yves-Alexis Perez -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of unsubscribe. Trouble? Contact [EMAIL PROTECTED]
2.6.17-rc3: cpufreq-set -g ondemand does not work
cpufreq-set -g ondemand fails on linux-2.6.17-rc3 PowerBook5,6, config see below. dmesg has: ondemand governor failed to load due to too long transition latency same with conservative. Both modules are loaded as lsmod shows. I will probably try to change the .config to make ondemand or conservative the default, but this might be a bug nevertheless, thus I am reporting. Any hints? Relevant .config: CONFIG_CPU_FREQ=y CONFIG_CPU_FREQ_TABLE=y CONFIG_CPU_FREQ_DEBUG=y CONFIG_CPU_FREQ_STAT=y CONFIG_CPU_FREQ_STAT_DETAILS=y # CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE is not set CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE=y CONFIG_CPU_FREQ_GOV_PERFORMANCE=m CONFIG_CPU_FREQ_GOV_POWERSAVE=m CONFIG_CPU_FREQ_GOV_USERSPACE=y CONFIG_CPU_FREQ_GOV_ONDEMAND=m CONFIG_CPU_FREQ_GOV_CONSERVATIVE=m CONFIG_CPU_FREQ_PMAC=y # CONFIG_PPC601_SYNC_FIX is not set pgp50JtA6FeQW.pgp Description: PGP signature
