On 07/17/2013 10:31 PM, 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. > > 2) If I run the hotplug test script, leaving CPU 0 always present, I > sometimes see: > >> root@localhost:~# for i in `seq 1 50`; do echo ITERATION $i; ./cpuonline.py; done >> ITERATION 1 >> echo 0 > /sys/devices/system/cpu/cpu2/online >> [ 458.910054] CPU2: shutdown >> echo 0 > /sys/devices/system/cpu/cpu1/online >> [ 461.004371] CPU1: shutdown >> echo 0 > /sys/devices/system/cpu/cpu3/online >> [ 463.027341] CPU3: shutdown >> echo 1 > /sys/devices/system/cpu/cpu1/online >> [ 465.061412] CPU1: Booted secondary processor >> echo 1 > /sys/devices/system/cpu/cpu2/online >> [ 467.095313] CPU2: Booted secondary processor >> [ 467.113243] ------------[ cut here ]------------ >> [ 467.117948] WARNING: CPU: 2 PID: 0 at kernel/time/tick-broadcast.c:667 tick_broadcast_oneshot_control+0x19c/0x1c4() >> [ 467.128352] Modules linked in: >> [ 467.131455] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 3.11.0-rc1-00022-g7487363-dirty #49 >> [ 467.139678] [<c0015620>] (unwind_backtrace+0x0/0xf8) from [<c001154c>] (show_stack+0x10/0x14) >> [ 467.148228] [<c001154c>] (show_stack+0x10/0x14) from [<c05135a8>] (dump_stack+0x80/0xc4) >> [ 467.156336] [<c05135a8>] (dump_stack+0x80/0xc4) from [<c0024590>] (warn_slowpath_common+0x64/0x88) >> [ 467.165300] [<c0024590>] (warn_slowpath_common+0x64/0x88) from [<c00245d0>] (warn_slowpath_null+0x1c/0x24) >> [ 467.174959] [<c00245d0>] (warn_slowpath_null+0x1c/0x24) from [<c00695e4>] (tick_broadcast_oneshot_control+0x19c/0x1c4) >> [ 467.185659] [<c00695e4>] (tick_broadcast_oneshot_control+0x19c/0x1c4) from [<c0067cdc>] (clockevents_notify+0x1b0/0x1dc) >> [ 467.196538] [<c0067cdc>] (clockevents_notify+0x1b0/0x1dc) from [<c034f348>] (cpuidle_idle_call+0x11c/0x168) >> [ 467.206292] [<c034f348>] (cpuidle_idle_call+0x11c/0x168) from [<c000f134>] (arch_cpu_idle+0x8/0x38) >> [ 467.215359] [<c000f134>] (arch_cpu_idle+0x8/0x38) from [<c0061038>] (cpu_startup_entry+0x60/0x134) >> [ 467.224325] [<c0061038>] (cpu_startup_entry+0x60/0x134) from [<800083d8>] (0x800083d8) >> [ 467.232227] ---[ end trace ea579be22a00e7fb ]--- >> echo 0 > /sys/devices/system/cpu/cpu1/online >> [ 469.126682] CPU1: shutdown > > I have found no solution for (1) (although I didn't look hard!). > > (2) can be solved with the following (at least 50 iterations of my test > script worked with this patch applied): Actually this warning is resulting from a bug in the tick broadcast code and has been solved with commit: https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/commit/?h=timers/urgent&id=ea8deb8dfa6b0e8d1b3d1051585706739b46656c This patch has been merged in timers/urgent branch but still need to merged with timers/core. The patch below does not fix the warning but prevents the tick warning to occur. Applying the patch above will fix your problem. >> diff --git a/arch/arm/mach-tegra/cpuidle-tegra114.c b/arch/arm/mach-tegra/cpuidle-tegra114.c >> index 658b205..896408d 100644 >> --- a/arch/arm/mach-tegra/cpuidle-tegra114.c >> +++ b/arch/arm/mach-tegra/cpuidle-tegra114.c >> @@ -66,8 +66,7 @@ static struct cpuidle_driver tegra_idle_driver = { >> .exit_latency = 500, >> .target_residency = 1000, >> .power_usage = 0, >> - .flags = CPUIDLE_FLAG_TIME_VALID | >> - CPUIDLE_FLAG_TIMER_STOP, >> + .flags = CPUIDLE_FLAG_TIME_VALID, >> .name = "powered-down", >> .desc = "CPU power gated", >> }, > > Here's my test script for reference: > > #!/usr/bin/env python > > import multiprocessing > import os > import sys > import time > > cpus = multiprocessing.cpu_count() > if cpus == 4: > socf = file('/sys/devices/soc0/soc_id') > soc = socf.readline().strip() > socf.close() > if True: #soc == '48': > gc = (11, 9, 1, 3, 7, 5, 13, 15) > else: > gc = (14, 10, 11, 9, 8, 1, 3, 2, 6, 7, 5, 4, 12, 13, 15) > elif cpus == 2: > gc = (1, 3) > else: > raise Exception("Invalid CPU count %d" % cpus) > > oldidx = len(gc) - 1 > oldmask = gc[oldidx] > > for newidx in range(len(gc)): > newmask = gc[newidx] > for cpu in range(cpus): > oldon = oldmask & (1 << cpu) > newon = newmask & (1 << cpu) > if oldon != newon: > if newon: > newonval = 1 > else: > newonval = 0 > cmd = "echo %d > /sys/devices/system/cpu/cpu%d/online" \ > % (newonval, cpu) > print cmd > os.system(cmd) > time.sleep(2) > oldidx = newidx > oldmask = newmask > -- <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
