On 07/22/2013 05:15 AM, Joseph Lo wrote: > On Fri, 2013-07-19 at 18:52 +0800, Daniel Lezcano wrote: >> On 07/19/2013 09:14 AM, Joseph Lo wrote: >>> On Thu, 2013-07-18 at 20:41 +0800, Daniel Lezcano wrote: >>>> On 07/18/2013 01:08 PM, Joseph Lo wrote: >>>>> On Thu, 2013-07-18 at 04:31 +0800, Stephen Warren wrote: >>>>>> On 07/17/2013 04:15 AM, Joseph Lo wrote: >>>>>>> On Wed, 2013-07-17 at 03:51 +0800, Stephen Warren wrote: >>>>>>>> On 07/16/2013 05:17 AM, Joseph Lo wrote: >>>>>>>>> On Tue, 2013-07-16 at 02:04 +0800, Stephen Warren wrote: >>>>>>>>>> On 06/25/2013 03:23 AM, Joseph Lo wrote: >>>>>>>>>>> Use the CPUIDLE_FLAG_TIMER_STOP and let the cpuidle framework >>>>>>>>>>> to handle the CLOCK_EVT_NOTIFY_BROADCAST_ENTER/EXIT when entering >>>>>>>>>>> this state. >>>>>> ... [ discussion of issues with Joesph's patches applied] >>>>>>> >>>>>>> OK. I did more stress tests last night and today. I found it cause by >>>>>>> the patch "ARM: tegra: cpuidle: use CPUIDLE_FLAG_TIMER_STOP flag" and >>>>>>> only impact the Tegra20 platform. The hot plug regression seems due to >>>>>>> this patch. After dropping this patch on top of v3.11-rc1, the Tegra20 >>>>>>> can back to normal. >>>>>>> >>>>>>> And the hop plug and suspend stress test can pass on Tegra30/114 too. >>>>>>> >>>>>>> Can the other two patch series for Tegra114 to support CPU idle power >>>>>>> down mode and system suspend still moving forward, not be blocked by >>>>>>> this patch? >>>>>>> >>>>>>> Looks the CPUIDLE_FLAG_TIMER_STOP flag still cause some other issue for >>>>>>> hot plug on Tegra20, I will continue to check this. You can just drop >>>>>>> this patch. >>>>>> >>>>>> OK, if I drop that patch, then everything on Tegra20 and Tegra30 seems >>>>>> fine again. >>>>>> >>>>>> However, I've found some new and exciting issue on Tegra114! >>>>>> >>>>>> With unmodified v3.11-rc1, I can do the following without issue: >>>>>> >>>>>> * Unplug/replug CPUs, so that I had all combinations of CPU 1, 2, 3 >>>>>> plugged/unpplugged (with CPU 0 always plugged). >>>>>> >>>>>> * Unplug/replug CPUs, so that I had all combinations of CPU 0, 1, 2, 3 >>>>>> plugged/unpplugged (with the obvious exception of never having all CPUs >>>>>> unplugged). >>>>>> >>>>>> However, if I try this with your Tegra114 cpuidle and suspend patches >>>>>> applied, I see the following issues: >>>>>> >>>>>> 1) If I boot, unplug CPU 0, then replug CPU 0, the system immediately >>>>>> hard-hangs. >>>>>> >>>>> Sorry, I didn't apply the hotplug stress test on CPU0 too much. Because >>>>> all of our use cases and stress tests are focused on secondary CPUs >>>>> only. >>>>> >>>>> After doing some tests, here is my summary. This issue happens after we >>>>> support CPU idle power-down mode and relates to PMC or flow controller I >>>>> believe. >>>>> >>>>> i) on top of v3.11-rc1 (only support WFI in CPU idle) >>>>> When hot unplug CPU0, the PMC can power gate and put it into reset >>>>> state. This is what I expect and also true on all the other secondary >>>>> CPUs. The flow controller can maintain the CPU power state machine as >>>>> what we want. >>>>> >>>>> ii) on top of v3.11-rc1 + CPU idle power down mode support >>>>> a) I saw most of the time the CPU0,1,2,3 were in power down and reset >>>>> status. That means the idle power down mode works fine. >>>>> >>>>> b) Testing with the CPU hotplug stress test with the secondary CPUs (not >>>>> include CPU0), the result is good too. >>>>> >>>>> c) Testing hot plug on CPU0 with CPUIDLE_FLAG_TIMER_STOP apply or not >>>>> apply (Note 1), the result shows not good to me. The CPU0 have already >>>>> gone into WFI and the flow controller is set as WAITFOREVENT mode. But >>>>> the PMC always can't power gate CPU0 and sometimes can put it into >>>>> reset, but sometimes can't. That's why you can see it hanging after >>>>> unplug CPU0 sometimes. >>>> >>>> Are sure coupled idle state support hotplug and especially the cpu0 >>>> hotplug ? >>> >>> Tegra114 didn't use coupled idle framework. >> >> Ok, so the problem occurs with the CPUIDLE_FLAG_TIMER_STOP flag only on >> tegra114, right ? >> >> Sorry, I am a bit lost :) >> > Here are the issues that happen after apply CPUIDLE_FLAG_TIMER_STOP. > 1) Tegra114/30 > The warning message at kernel/time/tick-broadcast.c:667 > tick_broadcast_oneshot_control could be triggered when doing CPU hot > plug stress test. With the fix for tick-broadcast.c [1] ? > 2) Tegra20 > The system is easy to stick or become lag. > The CPU hot plug is easy to cause system stick too. > > The fix I suggested in another mail looks can fix all the issues above. > I verified it again today on 3 different Tegra SoC platforms. Not sure your patch fixes the problem. I am wondering if there isn't a underlaying problem which surface with the flag. Thanks ! -- Daniel [1] https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=ea8deb8dfa6b0e8d1b3d1051585706739b46656c -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
