From: Sravan <asravan@codeaurora.org>
To: linux-pm@vger.kernel.org
Subject: avoid adding devices without pm_ops to dpm list
Date: Mon, 21 Apr 2014 17:37:06 +0530 [thread overview]
Message-ID: <535509EA.2090006@codeaurora.org> (raw)
Hello,
I have come across below code which looks can be optimized to reduce
suspend/resume latencies.
During device registration at boot up, device_add() is called.
In this device_add() function, device_pm_add() is called without
checking if the device has pm_ops or not.
Thus dpm_list is generated with all devices even if some devices don't
have pm_ops.
device_add() -> device_pm_add()-> generate dpm_list
During suspend/resume process, suspend/resume APIs are called for
devices present in dpm_list.
due to this, suspend/resume APIs for devices without pm_ops also called
and just return with NULL.
Can we optimize this code by adding *ONLY* devices with pm_ops to
dpm_list and ignore remaining?
It will help reduce suspend/resume latencies. I observed 10mS savings
with my debug code. It may change based on number of devices without pm_ops.
Let me know your opinion/suggestions on this.
---
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation
next reply other threads:[~2014-04-21 12:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-21 12:07 Sravan [this message]
2014-04-21 14:09 ` avoid adding devices without pm_ops to dpm list Alan Stern
2014-05-04 5:57 ` Sravan
2014-05-04 15:52 ` Alan Stern
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