FROMLIST: cpuidle: Deny idle entry when CPU already have IPI pending#883
Open
smankad-oss wants to merge 1 commit intoqualcomm-linux:tech/pm/powerfrom
Open
FROMLIST: cpuidle: Deny idle entry when CPU already have IPI pending#883smankad-oss wants to merge 1 commit intoqualcomm-linux:tech/pm/powerfrom
smankad-oss wants to merge 1 commit intoqualcomm-linux:tech/pm/powerfrom
Conversation
maulik-k-shah
force-pushed
the
tech/pm/power
branch
from
25fc1b7 to
823e2c5
Compare
…t pending CPU can get IPI interrupt from another CPU while it is executing cpuidle_select() or about to execute same. The selection do not account for pending interrupts and may continue to enter selected idle state only to exit immediately. Example trace collected when there is cross CPU IPI. [000] 154.892148: sched_waking: comm=sugov:4 pid=491 prio=-1 target_cpu=007 [000] 154.892148: ipi_raise: target_mask=00000000,00000080 (Function call interrupts) [007] 154.892162: cpu_idle: state=2 cpu_id=7 [007] 154.892208: cpu_idle: state=4294967295 cpu_id=7 [007] 154.892211: irq_handler_entry: irq=2 name=IPI [007] 154.892211: ipi_entry: (Function call interrupts) [007] 154.892213: sched_wakeup: comm=sugov:4 pid=491 prio=-1 target_cpu=007 [007] 154.892214: ipi_exit: (Function call interrupts) This impacts performance and the above count increments. commit ccde652 ("smp: Introduce a helper function to check for pending IPIs") already introduced a helper function to check the pending IPIs and it is used in pmdomain governor to deny the cluster level idle state when there is a pending IPI on any of cluster CPUs. This however does not stop CPU to enter CPU level idle state. Make use of same at CPUidle to deny the idle entry when there is already IPI pending. With change observing glmark2 [1] off screen scores improving in the range of 25% to 30% on Qualcomm lemans-evk board which is arm64 based having two clusters each with 4 CPUs. [1] https://github.com/glmark2/glmark2 Link: https://lore.kernel.org/r/20260403-cpuidle_ipi-v2-1-b3e44b032e2c@oss.qualcomm.com Signed-off-by: Maulik Shah <maulik.shah@oss.qualcomm.com> Signed-off-by: Sneh Mankad <sneh.mankad@oss.qualcomm.com>
smankad-oss
force-pushed
the
tech/pm/power
branch
from
af3deb7 to
87ffa40
Compare
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
CPU can get IPI interrupt from another CPU while it is executing cpuidle_select() or about to execute same. The selection do not account for pending interrupts and may continue to enter selected idle state only to exit immediately.
This impacts performance and the above count increments.
commit ccde652 ("smp: Introduce a helper function to check for pending IPIs") already introduced a helper function to check the pending IPIs and it is used in pmdomain governor to deny the cluster level idle state when there is a pending IPI on any of cluster CPUs.
This however does not stop CPU to enter CPU level idle state. Make use of same at CPUidle to deny the idle entry when there is already IPI pending.
With change observing glmark2 [1] off screen scores improving in the range of 25% to 30% on Qualcomm lemans-evk board which is arm64 based having two clusters each with 4 CPUs.
[1] https://github.com/glmark2/glmark2
Link: https://lore.kernel.org/r/20260403-cpuidle_ipi-v2-1-b3e44b032e2c@oss.qualcomm.com
Signed-off-by: Maulik Shah maulik.shah@oss.qualcomm.com
Signed-off-by: Sneh Mankad sneh.mankad@oss.qualcomm.com