On 2022.11.26 08:26 Rui wrote:
> On Wed, 2022-11-23 at 20:08 -0800, Doug Smythies wrote:
>> On 2022.11.21 04:23 Kajetan Puchalski wrote:
>>> On Wed, Nov 02, 2022 at 03:28:06PM +0000, Kajetan Puchalski wrote:
>>>
>>> [...]
>>>
>>>> v3 -> v4:
>>>> - remove the chunk of code skipping metrics updates when the CPU
>>>> was utilized
>>>> - include new test results and more benchmarks in the cover
>>>> letter
>>>
>>> [...]
>>>
>>> It's been some time so I just wanted to bump this, what do you
>>> think
>>> about this v4? Doug has already tested it, resuls for his machine
>>> are
>>> attached to the v3 thread.
>>
>> Hi All,
>>
>> I continued to test this and included the proposed ladder idle
>> governor in my continued testing.
>> (Which is why I added Rui as an addressee)
>
> Hi, Doug,
Hi Rui,
> Really appreciated your testing data on this.
> I have some dumb questions and I need your help so that I can better
> understand some of the graphs. :)
>
>> However, I ran out of time. Here is what I have:
>>
>> Kernel: 6.1-rc3 and with patch sets
>> Processor: Intel(R) Core(TM) i5-10600K CPU @ 4.10GHz
>> CPU scaling driver: intel_cpufreq
>> HWP disabled.
>> Unless otherwsie stated, performance CPU scaling govenor.
>>
>> Legend:
>> teo: the current teo idle governor
>> util-v4: the RFC utilization teo patch set version 4.
>> menu: the menu idle governor
>> ladder-old: the current ladder idle governor
>> ladder: the RFC ladder patchset.
>>
>> Workflow: shell-intensive serialized workloads.
>> Variable: PIDs per second.
>> Note: Single threaded.
>> Master reference: forced CPU affinity to 1 CPU.
This is the 1cpu on the graph.
>> Performance Results:
>> http://smythies.com/~doug/linux/idle/teo-util/graphs/pids-perf.png
>> Schedutil Results:
>> http://smythies.com/~doug/linux/idle/teo-util/graphs/pids-su.png
>
> what does 1cpu mean?
For shell-intensive serialized workflow or:
Dountil the list of tasks is finished:
Start the next task in the list of stuff to do (with a new PID).
Wait for it to finish
Enduntil
We know it represents a challenge for CPU frequency scaling drivers,
schedulers, and therefore idle drivers.
We also know that the best performance is achieved by overriding
the scheduler and forcing CPU affinity. I use this "best" case as the
master reference, using the label 1cpu on the graph.
>> Workflow: sleeping ebizzy 128 threads.
>> Variable: interval (uSecs).
>> Performance Results:
>> http://smythies.com/~doug/linux/idle/teo-util/graphs/ebizzy-128-perf.png
>> Performance power and idle data:
>> http://smythies.com/~doug/linux/idle/teo-util/ebizzy/perf/
>
> for the "Idle state 0/1/2/3 was too deep" graphs, may I know how you
> assert that an idle state is too deep/shallow?
I get those stats directly from the kernel driver statistics. For example:
$ grep . /sys/devices/system/cpu/cpu4/cpuidle/state*/above
/sys/devices/system/cpu/cpu4/cpuidle/state0/above:0
/sys/devices/system/cpu/cpu4/cpuidle/state1/above:38085
/sys/devices/system/cpu/cpu4/cpuidle/state2/above:7668
/sys/devices/system/cpu/cpu4/cpuidle/state3/above:6823
$ grep . /sys/devices/system/cpu/cpu4/cpuidle/state*/below
/sys/devices/system/cpu/cpu4/cpuidle/state0/below:72059
/sys/devices/system/cpu/cpu4/cpuidle/state1/below:246573
/sys/devices/system/cpu/cpu4/cpuidle/state2/below:7817
/sys/devices/system/cpu/cpu4/cpuidle/state3/below:0
I keep track of the changes per sample interval and graph
the sum for all CPUs as a percentage of the usage of
that idle state.
Because I can never remember what "above" and "below"
actually mean, I use the terms "was too shallow"
and "was too deep".
... Doug
On Sat, 2022-11-26 at 13:56 -0800, Doug Smythies wrote: > On 2022.11.26 08:26 Rui wrote: > > On Wed, 2022-11-23 at 20:08 -0800, Doug Smythies wrote: > > > On 2022.11.21 04:23 Kajetan Puchalski wrote: > > > > On Wed, Nov 02, 2022 at 03:28:06PM +0000, Kajetan Puchalski > > > > wrote: > > > > > > > > [...] > > > > > > > > > v3 -> v4: > > > > > - remove the chunk of code skipping metrics updates when the > > > > > CPU > > > > > was utilized > > > > > - include new test results and more benchmarks in the cover > > > > > letter > > > > > > > > [...] > > > > > > > > It's been some time so I just wanted to bump this, what do you > > > > think > > > > about this v4? Doug has already tested it, resuls for his > > > > machine > > > > are > > > > attached to the v3 thread. > > > > > > Hi All, > > > > > > I continued to test this and included the proposed ladder idle > > > governor in my continued testing. > > > (Which is why I added Rui as an addressee) > > > > Hi, Doug, > > Hi Rui, > > > Really appreciated your testing data on this. > > I have some dumb questions and I need your help so that I can > > better > > understand some of the graphs. :) > > > > > However, I ran out of time. Here is what I have: > > > > > > Kernel: 6.1-rc3 and with patch sets > > > Processor: Intel(R) Core(TM) i5-10600K CPU @ 4.10GHz > > > CPU scaling driver: intel_cpufreq > > > HWP disabled. > > > Unless otherwsie stated, performance CPU scaling govenor. > > > > > > Legend: > > > teo: the current teo idle governor > > > util-v4: the RFC utilization teo patch set version 4. > > > menu: the menu idle governor > > > ladder-old: the current ladder idle governor > > > ladder: the RFC ladder patchset. > > > > > > Workflow: shell-intensive serialized workloads. > > > Variable: PIDs per second. > > > Note: Single threaded. > > > Master reference: forced CPU affinity to 1 CPU. > > This is the 1cpu on the graph. > > > > Performance Results: > > > http://smythies.com/~doug/linux/idle/teo-util/graphs/pids-perf.png > > > Schedutil Results: > > > http://smythies.com/~doug/linux/idle/teo-util/graphs/pids-su.png > > > > what does 1cpu mean? > > For shell-intensive serialized workflow or: > > Dountil the list of tasks is finished: > Start the next task in the list of stuff to do (with a new PID). > Wait for it to finish > Enduntil > > We know it represents a challenge for CPU frequency scaling drivers, > schedulers, and therefore idle drivers. > > We also know that the best performance is achieved by overriding > the scheduler and forcing CPU affinity. I use this "best" case as the > master reference, using the label 1cpu on the graph. > Got it. > > > Workflow: sleeping ebizzy 128 threads. > > > Variable: interval (uSecs). > > > Performance Results: > > > http://smythies.com/~doug/linux/idle/teo-util/graphs/ebizzy-128-perf.png > > > Performance power and idle data: > > > http://smythies.com/~doug/linux/idle/teo-util/ebizzy/perf/ > > > > for the "Idle state 0/1/2/3 was too deep" graphs, may I know how > > you > > assert that an idle state is too deep/shallow? > > I get those stats directly from the kernel driver statistics. For > example: > > $ grep . /sys/devices/system/cpu/cpu4/cpuidle/state*/above > /sys/devices/system/cpu/cpu4/cpuidle/state0/above:0 > /sys/devices/system/cpu/cpu4/cpuidle/state1/above:38085 > /sys/devices/system/cpu/cpu4/cpuidle/state2/above:7668 > /sys/devices/system/cpu/cpu4/cpuidle/state3/above:6823 > > $ grep . /sys/devices/system/cpu/cpu4/cpuidle/state*/below > /sys/devices/system/cpu/cpu4/cpuidle/state0/below:72059 > /sys/devices/system/cpu/cpu4/cpuidle/state1/below:246573 > /sys/devices/system/cpu/cpu4/cpuidle/state2/below:7817 > /sys/devices/system/cpu/cpu4/cpuidle/state3/below:0 > > I keep track of the changes per sample interval and graph > the sum for all CPUs as a percentage of the usage of > that idle state. > > Because I can never remember what "above" and "below" > actually mean, I use the terms "was too shallow" > and "was too deep". I just checked the code. My understanding is that "above" means the previous idle state residency is too short, and a shallower state would have been a better match. "below" means the previous idle state residency is too long, and a deeper state would have been a better match. So probably "above" means "should be shallower" or "was too deep", and "below" means "should be deeper" or "was to shallow"? thanks, rui
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