Re: iWave RZ/G1M hrtimers


Daniel Wagner <wagi@...>
 

On 05/04/2018 12:16 PM, Daniel Wagner wrote:
Hi Biju,
Not sure if I ping the right person about this problem.
I am doing some realtime testing on the iWave RZ/G1M board and noticed
quite high latency values for cyclictest (around 3ms).
As it turns out there is no hrtimer clock source available. Just the
arch cp8 clock source. The timer subsystem then decides to set the
resolution of the clocksource to 4000000 nsecs which explains the rather
bad value for cyclictest.
clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles:
0x24e6a1710, max_idle_ns: 440795202120 ns
sched_clock: 56 bits at 10MHz, resolution 100ns, wraps every 4398046511100ns
Switching to timer-based delay loop, resolution 100ns
# cat current_clocksource
arch_sys_counter
# cat available_clocksource
arch_sys_counter jiffies
# cat /proc/timer_list
Timer List Version: v0.8
HRTIMER_MAX_CLOCK_BASES: 4
now at 1705568146462 nsecs
cpu: 0
clock 0:
.base: dfbcbe40
.index: 0
.resolution: 4000000 nsecs
.get_time: ktime_get
.offset: 0 nsecs
The question is do I miss some magic CONFIG option or is the support not
yet in v4.4-cip ?
Forgot to mention. I am using the shmobile_defconfig configuration with some mods on top of it:

# systemd stuff
CONFIG_CGROUPS=y
CONFIG_CGROUP_DEBUG=n
CONFIG_CGROUP_FREEZER=n
CONFIG_INOTIFY_USER=y
CONFIG_FHANDLE=y
CONFIG_CRYPTO_USER_API_HASH=y
CONFIG_CRYPTO_HMAC=y
CONFIG_AUTOFS4_FS=y
CONFIG_TMPFS_XATTR=y

# -rt tunnings
CONFIG_DEBUG_ATOMIC_SLEEP=y
CONFIG_DEBUG_LOCK_ALLOC=n
CONFIG_PROVE_LOCKING=n
CONFIG_LOCKDEP=n

CONFIG_CPU_FREQ=n
CONFIG_CPU_IDLE=n

CONFIG_NO_HZ=n
CONFIG_HZ_PERIODIC=y

CONFIG_HZ_250=y
CONFIG_HZ=250

CONFIG_HIGH_RES_TIMERS=y

CONFIG_SUSPEND=n
CONFIG_HIBERNATION=n
CONFIG_PM=n

CONFIG_PREEMPT_RT_FULL=y

# root nfs
CONFIG_NFS_FS=y
CONFIG_NFS_V4=y
CONFIG_NFS_V4_1=y
CONFIG_NFS_V4_2=y

# some debugging stuff
CONFIG_FTRACE=y
CONFIG_FUNCTION_TRACER=y
CONFIG_SCHED_TRACER=y

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