On Tue, Feb 28, 2023 at 8:34 PM Zhuo, Qiuxu <qiuxu.zhuo@xxxxxxxxx> wrote: > > > From: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx> > > Sent: Tuesday, February 28, 2023 10:27 PM > > To: Zhuo, Qiuxu <qiuxu.zhuo@xxxxxxxxx> > > Cc: linux-kernel@xxxxxxxxxxxxxxx; Frederic Weisbecker <frederic@xxxxxxxxxx>; > > Lai Jiangshan <jiangshanlai@xxxxxxxxx>; linux-doc@xxxxxxxxxxxxxxx; Paul E. > > McKenney <paulmck@xxxxxxxxxx>; rcu@xxxxxxxxxxxxxxx > > Subject: Re: [PATCH RFC v2] rcu: Add a minimum time for marking boot as > > completed > > > > On Tue, Feb 28, 2023 at 1:40 AM Zhuo, Qiuxu <qiuxu.zhuo@xxxxxxxxx> wrote: > > > > > [...] > > > My testing showed the positive result that the OS boot time was > > > reduced by ~4.6% on my side after applying Joel’s patch. > > > > Wow, this is great! I am guessing you have CONFIG_RCU_LAZY disabled, > > when you tested. If so, that is great news that expediting RCU for a bit longer > > improves boot time! Please confirm that your config had LAZY disabled. > > > > I confirm that CONFIG_RCU_LAZY kernel configuration was disabled in my testing. > All the kernel configurations for RCU used in my testing are as below: Thank you! Good to know there is improvement in *existing code*, that's the power of upstream... new features fix/improve old ones sometimes. Any case, I will include all your data in v3. Thanks! - Joel > > # > # RCU Subsystem > # > CONFIG_TREE_RCU=y > CONFIG_PREEMPT_RCU=y > CONFIG_RCU_EXPERT=y > CONFIG_SRCU=y > CONFIG_TREE_SRCU=y > CONFIG_TASKS_RCU_GENERIC=y > # CONFIG_FORCE_TASKS_RCU is not set > CONFIG_TASKS_RCU=y > # CONFIG_FORCE_TASKS_RUDE_RCU is not set > # CONFIG_FORCE_TASKS_TRACE_RCU is not set > CONFIG_TASKS_TRACE_RCU=y > CONFIG_RCU_STALL_COMMON=y > CONFIG_RCU_NEED_SEGCBLIST=y > CONFIG_RCU_FANOUT=32 > CONFIG_RCU_FANOUT_LEAF=16 > # CONFIG_RCU_BOOST is not set > CONFIG_RCU_BOOT_END_DELAY=20000 > CONFIG_RCU_NOCB_CPU=y > # CONFIG_RCU_NOCB_CPU_DEFAULT_ALL is not set > # CONFIG_TASKS_TRACE_RCU_READ_MB is not set > # CONFIG_RCU_LAZY is not set > # end of RCU Subsystem > > -Qiuxu
