Hi guys
Does anyone know how to assign a high resolution clocksource to a HVM guest?
In my environment, the RHEL6's HVM guest kernel is 2.6.32.12 based, which is
the tickles kernel.
I got the timer information of this HVM guest as following:
When I "cat
/sys/devices/system/clocksource/clocksource0/available_clocksource", it shows
three available clocksources:
tsc hpet acpi_pm jiffies
and the current time source is, "cat
/sys/devices/system/clocksource/clocksource0/current_clocksource"
tsc
However, when I "cat /proc/timer_list":
It shows the resolution as ".resolution: 999848 nsecs", which is low resolution.
The event_handler is tick_handle_periodic, which is not tickles one-shot mode.
In the periodic mode, it triggers 1000 timer interrupts per second, that will
bring in some overhead.
The nohz_mode is 0, which means "dynamic ticks" was not enabled.
So, my question is that, can I assign a high resolution timer to HVM guest? How
can the tickles kernel use non-periodic event handler, like "hrtimer_interrupt"?
Detail Information from "cat /proc/timer_list"
________________________________________________________________________________________________________________
Timer List Version: v0.5
HRTIMER_MAX_CLOCK_BASES: 2
now at 15852107490831 nsecs
cpu: 0
clock 0:
.base: ffff880001e11e88
.index: 0
.resolution: 999848 nsecs
.get_time: ktime_get_real
.offset: 0 nsecs
active timers:
#0: <ffff88007bc69d18>, hrtimer_wakeup, S:01, hrtimer_start_range_ns, java/1147
# expires at 1304150196954680000-1304150196954730000 nsecs [in
1304134344847189169 to 1304134344847239169 nsecs]
#1: <ffff88003766dd18>, hrtimer_wakeup, S:01, hrtimer_start_range_ns, java/1161
# expires at 1304150263786719000-1304150263786769000 nsecs [in
1304134411679228169 to 1304134411679278169 nsecs]
#2: <ffff88007bfafd18>, hrtimer_wakeup, S:01, hrtimer_start_range_ns, java/1160
# expires at 1304150263789719000-1304150263789769000 nsecs [in
1304134411682228169 to 1304134411682278169 nsecs]
clock 1:
.base: ffff880001e11ec8
.index: 1
.resolution: 999848 nsecs
.get_time: ktime_get
.offset: 0 nsecs
active timers:
#0: init_task_group, sched_rt_period_timer, S:01, __enqueue_rt_entity,
swapper/1
# expires at 15853000000000-15853000000000 nsecs [in 892509169 to 892509169
nsecs]
#1: <ffff88007b7bba68>, hrtimer_wakeup, S:01, hrtimer_start_range_ns,
abrtd/1115
# expires at 15857231144038-15857331144038 nsecs [in 5123653207 to 5223653207
nsecs]
#2: <ffff8800377a3a68>, hrtimer_wakeup, S:01, hrtimer_start_range_ns,
avahi-daemon/998
# expires at 17409770144038-17409870144038 nsecs [in 1557662653207 to
1557762653207 nsecs]
#3: <ffff88007a0ad918>, hrtimer_wakeup, S:01, hrtimer_start_range_ns,
rsyslogd/897
# expires at 86414794559634-86414894559634 nsecs [in 70562687068803 to
70562787068803 nsecs]
.expires_next : 9223372036854775807 nsecs
.hres_active : 0
.nr_events : 0
.nr_retries : 0
.nr_hangs : 0
.max_hang_time : 0 nsecs
.nohz_mode : 0
.idle_tick : 0 nsecs
.tick_stopped : 0
.idle_jiffies : 0
.idle_calls : 0
.idle_sleeps : 0
.idle_entrytime : 15852106973443 nsecs
.idle_waketime : 0 nsecs
.idle_exittime : 0 nsecs
.idle_sleeptime : 2015652774896 nsecs
.iowait_sleeptime: 988743384 nsecs
.last_jiffies : 0
.next_jiffies : 0
.idle_expires : 0 nsecs
jiffies: 4310519631
cpu: 1
clock 0:
.base: ffff880001e31e88
.index: 0
.resolution: 999848 nsecs
.get_time: ktime_get_real
.offset: 0 nsecs
active timers:
#0: <ffff88007bcafd18>, hrtimer_wakeup, S:01, hrtimer_start_range_ns, java/1154
# expires at 1304150196915577000-1304150196915627000 nsecs [in
1304134344808086169 to 1304134344808136169 nsecs]
#1: <ffff88007a07fd18>, hrtimer_wakeup, S:01, hrtimer_start_range_ns,
automount/1090
# expires at 1304150197124171000-1304150197124221000 nsecs [in
1304134345016680169 to 1304134345016730169 nsecs]
#2: <ffff880037493d18>, hrtimer_wakeup, S:01, hrtimer_start_range_ns,
automount/1089
# expires at 1304150238123676000-1304150238123726000 nsecs [in
1304134386016185169 to 1304134386016235169 nsecs]
#3: <ffff88007baf9d18>, hrtimer_wakeup, S:01, hrtimer_start_range_ns, rs:main
Q:Reg/1854
# expires at 1304150245664082612-1304150245664132612 nsecs [in
1304134393556591781 to 1304134393556641781 nsecs]
#4: <ffff88007b947d18>, hrtimer_wakeup, S:01, hrtimer_start_range_ns, java/1158
# expires at 1304152363782719000-1304152363782769000 nsecs [in
1304136511675228169 to 1304136511675278169 nsecs]
clock 1:
.base: ffff880001e31ec8
.index: 1
.resolution: 999848 nsecs
.get_time: ktime_get
.offset: 0 nsecs
active timers:
#0: <ffff88007b9a7a68>, hrtimer_wakeup, S:01, hrtimer_start_range_ns, hald/1031
# expires at 15856231144038-15856261114038 nsecs [in 4123653207 to 4153623207
nsecs]
#1: <ffff880037ba5a68>, hrtimer_wakeup, S:01, hrtimer_start_range_ns,
rpcbind/915
# expires at 15871360185906-15871390185905 nsecs [in 19252695075 to
19282695074 nsecs]
.expires_next : 9223372036854775807 nsecs
.hres_active : 0
.nr_events : 0
.nr_retries : 0
.nr_hangs : 0
.max_hang_time : 0 nsecs
.nohz_mode : 0
.idle_tick : 0 nsecs
.tick_stopped : 0
.idle_jiffies : 0
.idle_calls : 0
.idle_sleeps : 0
.idle_entrytime : 15852105792015 nsecs
.idle_waketime : 0 nsecs
.idle_exittime : 0 nsecs
.idle_sleeptime : 15827991317141 nsecs
.iowait_sleeptime: 3221171737 nsecs
.last_jiffies : 0
.next_jiffies : 0
.idle_expires : 0 nsecs
jiffies: 4310519631
Tick Device: mode: 0
Broadcast device
Clock Event Device: hpet
max_delta_ns: 34359738352
min_delta_ns: 5000
mult: 268435456
shift: 32
mode: 2
next_event: 9223372036854775807 nsecs
set_next_event: hpet_legacy_next_event
set_mode: hpet_legacy_set_mode
event_handler: tick_handle_periodic_broadcast
tick_broadcast_mask: 00000003
tick_broadcast_oneshot_mask: 00000000
Tick Device: mode: 0
Per CPU device: 0
Clock Event Device: lapic
max_delta_ns: 1341975280
min_delta_ns: 2399
mult: 26847583
shift: 32
mode: 1
next_event: 9223372036854775807 nsecs
set_next_event: lapic_next_event
set_mode: lapic_timer_setup
event_handler: tick_handle_periodic
Tick Device: mode: 0
Per CPU device: 1
Clock Event Device: lapic
max_delta_ns: 1341975280
min_delta_ns: 2399
mult: 26847583
shift: 32
mode: 1
next_event: 9223372036854775807 nsecs
set_next_event: lapic_next_event
set_mode: lapic_timer_setup
event_handler: tick_handle_periodic
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