+ John and Sumit for comments,
On 24 June 2015 at 06:22, Alex Shi alex.shi@linaro.org wrote:
CC AmitP and linaro kernel,
Apparently, some APPs are very aggressive using v3.15 kernel's header, since PR_SET_THP_DISABLE is introduced from 3.15. and PR_SET_TIMERSLACK_PID never appears in mainline kernel, only in android.
Amit,
Guess we need to revert this SET_TIMERSLACK_PID if APP keep using DHP_DIS. Any concern/suggestion of this issue?
I'm not sure if reverting SET_TIMERSLACK_PID patch in lsk-3.10-android kernel is a good call here. A quick search show that AOSP master still use SET_TIMERSLACK_PID to set/change the scheduling priority[1] of the background binder and art threads, to name a few.
If we are running into significant performance hit with APPs using PR_SET_THP_DISABLE on Android kernel, with conflicting prctl value of SET_TIMERSLACK_PID, then we should either just submit a change in AOSP to update SET_TIMERSLACK_PID value accordingly and/or also try to backport PR_SET_THP_DISABLE to aosp/android-3.10 kernel if we have a significant usecase for that. Let me know if it make any sense.
Regards, Amit Pundir
[1] https://android.googlesource.com/platform/system/core/+/master/libcutils/sch...
Thanks!
On 06/23/2015 05:46 PM, Mark Brown wrote:
Hi,
Adding Kevin and Alex - I'm not responsible for the LSK any more, Kevin has taken over.
Thanks, Mark
On 23 June 2015 at 10:32, YiPing Xu <xuyiping@hisilicon.com mailto:xuyiping@hisilicon.com> wrote:
hi In the commit below, LSK3.10 add PR_SET_TIMERSLACK_PID to prctl, but the code does not really work. https://git.linaro.org/kernel/linux-linaro-stable.git/commitdiff/800f7e9e8d8c607b70d384a62db02490a73dfbab And the PR_SET_TIMERSLACK_PID has value 41, which is used as PR_SET_THP_DISABLE in kernel main tree. see https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/prctl.h -- line 184 In lsk-v3.10-15.05, the commit below make PR_SET_TIMERSLACK_PID works. We find a lot of APP use value "41" as PR_SET_THP_DISABLE, and the kernel get a poor performance https://git.linaro.org/kernel/linux-linaro-stable.git/commit/e1a60cbe0312adbf471ee057c5d7b917ae5e80c5 Shall we revert the PR_SET_TIMERSLACK_PID code, or keep it as same with the kernel main tree?