In current hyper-v time sync service,it only gets the initial clock time
from the host. It didn't process the following time samples. This change
introduced a module parameter called host_time_sync. If it is set to true,
the guest will periodically sychronize it's time with the host clock using
host time sample. By default it is disabled, because we still recommend
user to configure NTP for time synchronization.
Signed-off-by: Thomas Shao <[email protected]>
Reviewed-by: K. Y. Srinivasan <[email protected]>
---
drivers/hv/hv_util.c | 114 +++++++++++++++++++++++++++++++++++++++++---
kernel/time/timekeeping.c | 1 +
2 files changed, 107 insertions(+), 8 deletions(-)
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index 3b9c9ef..1d8390c 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -51,11 +51,30 @@
#define HB_WS2008_MAJOR 1
#define HB_WS2008_VERSION (HB_WS2008_MAJOR << 16 | HB_MINOR)
+#define TIMESAMPLE_INTERVAL 5000000000L /* 5s in nanosecond */
+
+/*host sends time sample for every 5s.So the max polling interval
+ *is 128*5 = 640s.
+*/
+#define TIME_ADJ_MAX_INTERVAL 128 /*Max polling interval */
+
static int sd_srv_version;
static int ts_srv_version;
static int hb_srv_version;
static int util_fw_version;
+/*host sends time sample for every 5s.So the initial polling interval
+ *is 5s.
+*/
+static s32 adj_interval = 1;
+
+/*The host_time_sync module parameter is used to control the time
+ sync between host and guest.
+*/
+static bool host_time_sync;
+module_param(host_time_sync, bool, (S_IRUGO | S_IWUSR));
+MODULE_PARM_DESC(host_time_sync, "If the guest sync time with host");
+
static void shutdown_onchannelcallback(void *context);
static struct hv_util_service util_shutdown = {
.util_cb = shutdown_onchannelcallback,
@@ -163,15 +182,61 @@ static void shutdown_onchannelcallback(void *context)
/*
* Set guest time to host UTC time.
*/
-static inline void do_adj_guesttime(u64 hosttime)
+static inline void do_adj_guesttime(u64 hosttime, bool forceSync)
{
- s64 host_tns;
- struct timespec host_ts;
+ s64 host_tns, guest_tns, diff;
+ struct timespec host_ts, guest_ts;
+ struct timex txc;
+ s64 tickchg;
+ int diff_sign;
host_tns = (hosttime - WLTIMEDELTA) * 100;
host_ts = ns_to_timespec(host_tns);
- do_settimeofday(&host_ts);
+ if (forceSync) {
+ do_settimeofday(&host_ts);
+ } else {
+ guest_ts = CURRENT_TIME;
+ guest_tns = timespec_to_ns(&guest_ts);
+ diff = host_tns - guest_tns;
+ if (diff >= 0) {
+ diff_sign = 1;
+ } else {
+ diff_sign = -1;
+ diff = -diff;
+ }
+
+ /*1s in nanosecond */
+ if (diff > 1000000000 || diff < -1000000000) {
+ do_settimeofday(&host_ts);
+ return;
+ }
+
+ /*1ms in nanosecond */
+ if (diff > 1000000 || diff < -1000000) {
+ /* get the current tick value */
+ txc.modes = 0;
+ do_adjtimex(&txc);
+
+ tickchg = diff * TICK_USEC /
+ (TIMESAMPLE_INTERVAL * adj_interval);
+
+ if (tickchg > TICK_USEC/10)
+ tickchg = TICK_USEC/10;
+
+ if (txc.tick == TICK_USEC + diff_sign * tickchg)
+ return;
+
+ txc.modes = ADJ_TICK;
+ txc.tick = TICK_USEC + diff_sign * tickchg;
+
+ do_adjtimex(&txc);
+ } else {
+ /* double the polling interval*/
+ if (adj_interval < TIME_ADJ_MAX_INTERVAL)
+ adj_interval = adj_interval * 2;
+ }
+ }
}
/*
@@ -179,8 +244,9 @@ static inline void do_adj_guesttime(u64 hosttime)
*/
struct adj_time_work {
- struct work_struct work;
+ struct work_struct work;
u64 host_time;
+ bool forceSync;
};
static void hv_set_host_time(struct work_struct *work)
@@ -188,7 +254,7 @@ static void hv_set_host_time(struct work_struct *work)
struct adj_time_work *wrk;
wrk = container_of(work, struct adj_time_work, work);
- do_adj_guesttime(wrk->host_time);
+ do_adj_guesttime(wrk->host_time, wrk->forceSync);
kfree(wrk);
}
@@ -202,11 +268,14 @@ static void hv_set_host_time(struct work_struct *work)
* thing is, systime is automatically set to emulated hardware clock which may
* not be UTC time or in the same time zone. So, to override these effects, we
* use the first 50 time samples for initial system time setting.
+ * If the host_time_sync module parameter is set, we will use the host time
+ * samples to adjust guest time after the first 50 samples.
*/
static inline void adj_guesttime(u64 hosttime, u8 flags)
{
struct adj_time_work *wrk;
static s32 scnt = 50;
+ static s32 sample_count;
wrk = kmalloc(sizeof(struct adj_time_work), GFP_ATOMIC);
if (wrk == NULL)
@@ -214,6 +283,7 @@ static inline void adj_guesttime(u64 hosttime, u8 flags)
wrk->host_time = hosttime;
if ((flags & ICTIMESYNCFLAG_SYNC) != 0) {
+ wrk->forceSync = true;
INIT_WORK(&wrk->work, hv_set_host_time);
schedule_work(&wrk->work);
return;
@@ -221,10 +291,38 @@ static inline void adj_guesttime(u64 hosttime, u8 flags)
if ((flags & ICTIMESYNCFLAG_SAMPLE) != 0 && scnt > 0) {
scnt--;
+ wrk->forceSync = true;
INIT_WORK(&wrk->work, hv_set_host_time);
schedule_work(&wrk->work);
- } else
- kfree(wrk);
+ return;
+ }
+
+ if (host_time_sync) {
+ /*
+ * Use the Hyper-V time sample to adjust the guest time. The
+ * algorithm is: If the sample offsets exceeds 1 second, we
+ * directly set the clock to the server time. If the offset is
+ * less than 1ms, we ignore the time sample. Otherwise we adjust
+ * the clock.
+ */
+
+ if ((flags & ICTIMESYNCFLAG_SAMPLE) != 0) {
+ if (sample_count < adj_interval) {
+ sample_count++;
+ goto cleanup;
+ }
+ /* reset the polling interval */
+ sample_count = 0;
+ wrk->forceSync = false;
+ INIT_WORK(&wrk->work, hv_set_host_time);
+ schedule_work(&wrk->work);
+ return;
+ }
+ }
+
+cleanup:
+ kfree(wrk);
+
}
/*
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index ec1791f..381a1ca 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -1786,6 +1786,7 @@ int do_adjtimex(struct timex *txc)
return ret;
}
+EXPORT_SYMBOL(do_adjtimex);
#ifdef CONFIG_NTP_PPS
/**
--
1.7.1
On Tue, Oct 14, 2014 at 01:23:46AM -0700, Thomas Shao wrote:
> --- a/kernel/time/timekeeping.c
> +++ b/kernel/time/timekeeping.c
> @@ -1786,6 +1786,7 @@ int do_adjtimex(struct timex *txc)
>
> return ret;
> }
> +EXPORT_SYMBOL(do_adjtimex);
EXPORT_SYMBOL_GPL()?
> -----Original Message-----
> From: Greg KH [mailto:[email protected]]
> Sent: Tuesday, October 14, 2014 3:35 PM
> To: Thomas Shao
> Cc: [email protected]; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; KY Srinivasan
> Subject: Re: [PATCH] hyperv: Implement Time Synchronization using host
> time sample
>
> On Tue, Oct 14, 2014 at 01:23:46AM -0700, Thomas Shao wrote:
> > --- a/kernel/time/timekeeping.c
> > +++ b/kernel/time/timekeeping.c
> > @@ -1786,6 +1786,7 @@ int do_adjtimex(struct timex *txc)
> >
> > return ret;
> > }
> > +EXPORT_SYMBOL(do_adjtimex);
>
> EXPORT_SYMBOL_GPL()?
Oh, yes, I should use EXPORT_SYMBOL_GPL. I'll send a new patch. Thanks Greg.
On Tue, 14 Oct 2014, Thomas Shao wrote:
> > -----Original Message-----
> > From: Greg KH [mailto:[email protected]]
> > Sent: Tuesday, October 14, 2014 3:35 PM
> > To: Thomas Shao
> > Cc: [email protected]; [email protected];
> > [email protected]; [email protected]; [email protected];
> > [email protected]; KY Srinivasan
> > Subject: Re: [PATCH] hyperv: Implement Time Synchronization using host
> > time sample
> >
> > On Tue, Oct 14, 2014 at 01:23:46AM -0700, Thomas Shao wrote:
> > > --- a/kernel/time/timekeeping.c
> > > +++ b/kernel/time/timekeeping.c
> > > @@ -1786,6 +1786,7 @@ int do_adjtimex(struct timex *txc)
> > >
> > > return ret;
> > > }
> > > +EXPORT_SYMBOL(do_adjtimex);
> >
> > EXPORT_SYMBOL_GPL()?
>
> Oh, yes, I should use EXPORT_SYMBOL_GPL. I'll send a new patch. Thanks Greg.
And please make that export a separate patch.
Thanks,
tglx
> -----Original Message-----
> From: Thomas Gleixner [mailto:[email protected]]
> Sent: Tuesday, October 14, 2014 5:14 PM
> To: Thomas Shao
> Cc: Greg KH; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected]; KY Srinivasan
> Subject: RE: [PATCH] hyperv: Implement Time Synchronization using host
> time sample
>
> On Tue, 14 Oct 2014, Thomas Shao wrote:
> > > -----Original Message-----
> > > From: Greg KH [mailto:[email protected]]
> > > Sent: Tuesday, October 14, 2014 3:35 PM
> > > To: Thomas Shao
> > > Cc: [email protected]; [email protected];
> > > [email protected]; [email protected]; [email protected];
> > > [email protected]; KY Srinivasan
> > > Subject: Re: [PATCH] hyperv: Implement Time Synchronization using
> > > host time sample
> > >
> > > On Tue, Oct 14, 2014 at 01:23:46AM -0700, Thomas Shao wrote:
> > > > --- a/kernel/time/timekeeping.c
> > > > +++ b/kernel/time/timekeeping.c
> > > > @@ -1786,6 +1786,7 @@ int do_adjtimex(struct timex *txc)
> > > >
> > > > return ret;
> > > > }
> > > > +EXPORT_SYMBOL(do_adjtimex);
> > >
> > > EXPORT_SYMBOL_GPL()?
> >
> > Oh, yes, I should use EXPORT_SYMBOL_GPL. I'll send a new patch. Thanks
> Greg.
>
> And please make that export a separate patch.
>
OK. I'll send the separate patch. For my original patch, do I need to wait? Since it depends on the
Export patch to build.
> Thanks,
>
> tglx
These old duplicated patches are accidentally send by the mail server... Sorry for that.
> -----Original Message-----
> From: Thomas Shao [mailto:[email protected]]
> Sent: Tuesday, October 14, 2014 1:49 PM
> To: [email protected]; [email protected]; linux-
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; KY Srinivasan
> Cc: Thomas Shao
> Subject: [PATCH] hyperv: Implement Time Synchronization using host time
> sample
>
> In current hyper-v time sync service,it only gets the initial clock time from the
> host. It didn't process the following time samples. This change introduced a
> module parameter called host_time_sync. If it is set to true, the guest will
> periodically sychronize it's time with the host clock using host time sample. By
> default it is disabled, because we still recommend user to configure NTP for
> time synchronization.
>
> Signed-off-by: Thomas Shao <[email protected]>
> Reviewed-by: K. Y. Srinivasan <[email protected]>
> ---
> drivers/hv/hv_util.c | 114
> +++++++++++++++++++++++++++++++++++++++++---
> kernel/time/timekeeping.c | 1 +
> 2 files changed, 107 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c index 3b9c9ef..1d8390c
> 100644
> --- a/drivers/hv/hv_util.c
> +++ b/drivers/hv/hv_util.c
> @@ -51,11 +51,30 @@
> #define HB_WS2008_MAJOR 1
> #define HB_WS2008_VERSION (HB_WS2008_MAJOR << 16 | HB_MINOR)
>
> +#define TIMESAMPLE_INTERVAL 5000000000L /* 5s in nanosecond */
> +
> +/*host sends time sample for every 5s.So the max polling interval *is
> +128*5 = 640s.
> +*/
> +#define TIME_ADJ_MAX_INTERVAL 128 /*Max polling interval */
> +
> static int sd_srv_version;
> static int ts_srv_version;
> static int hb_srv_version;
> static int util_fw_version;
>
> +/*host sends time sample for every 5s.So the initial polling interval
> +*is 5s.
> +*/
> +static s32 adj_interval = 1;
> +
> +/*The host_time_sync module parameter is used to control the time
> + sync between host and guest.
> +*/
> +static bool host_time_sync;
> +module_param(host_time_sync, bool, (S_IRUGO | S_IWUSR));
> +MODULE_PARM_DESC(host_time_sync, "If the guest sync time with host");
> +
> static void shutdown_onchannelcallback(void *context); static struct
> hv_util_service util_shutdown = {
> .util_cb = shutdown_onchannelcallback, @@ -163,15 +182,61 @@
> static void shutdown_onchannelcallback(void *context)
> /*
> * Set guest time to host UTC time.
> */
> -static inline void do_adj_guesttime(u64 hosttime)
> +static inline void do_adj_guesttime(u64 hosttime, bool forceSync)
> {
> - s64 host_tns;
> - struct timespec host_ts;
> + s64 host_tns, guest_tns, diff;
> + struct timespec host_ts, guest_ts;
> + struct timex txc;
> + s64 tickchg;
> + int diff_sign;
>
> host_tns = (hosttime - WLTIMEDELTA) * 100;
> host_ts = ns_to_timespec(host_tns);
>
> - do_settimeofday(&host_ts);
> + if (forceSync) {
> + do_settimeofday(&host_ts);
> + } else {
> + guest_ts = CURRENT_TIME;
> + guest_tns = timespec_to_ns(&guest_ts);
> + diff = host_tns - guest_tns;
> + if (diff >= 0) {
> + diff_sign = 1;
> + } else {
> + diff_sign = -1;
> + diff = -diff;
> + }
> +
> + /*1s in nanosecond */
> + if (diff > 1000000000 || diff < -1000000000) {
> + do_settimeofday(&host_ts);
> + return;
> + }
> +
> + /*1ms in nanosecond */
> + if (diff > 1000000 || diff < -1000000) {
> + /* get the current tick value */
> + txc.modes = 0;
> + do_adjtimex(&txc);
> +
> + tickchg = diff * TICK_USEC /
> + (TIMESAMPLE_INTERVAL *
> adj_interval);
> +
> + if (tickchg > TICK_USEC/10)
> + tickchg = TICK_USEC/10;
> +
> + if (txc.tick == TICK_USEC + diff_sign * tickchg)
> + return;
> +
> + txc.modes = ADJ_TICK;
> + txc.tick = TICK_USEC + diff_sign * tickchg;
> +
> + do_adjtimex(&txc);
> + } else {
> + /* double the polling interval*/
> + if (adj_interval < TIME_ADJ_MAX_INTERVAL)
> + adj_interval = adj_interval * 2;
> + }
> + }
> }
>
> /*
> @@ -179,8 +244,9 @@ static inline void do_adj_guesttime(u64 hosttime)
> */
>
> struct adj_time_work {
> - struct work_struct work;
> + struct work_struct work;
> u64 host_time;
> + bool forceSync;
> };
>
> static void hv_set_host_time(struct work_struct *work) @@ -188,7 +254,7
> @@ static void hv_set_host_time(struct work_struct *work)
> struct adj_time_work *wrk;
>
> wrk = container_of(work, struct adj_time_work, work);
> - do_adj_guesttime(wrk->host_time);
> + do_adj_guesttime(wrk->host_time, wrk->forceSync);
> kfree(wrk);
> }
>
> @@ -202,11 +268,14 @@ static void hv_set_host_time(struct work_struct
> *work)
> * thing is, systime is automatically set to emulated hardware clock which
> may
> * not be UTC time or in the same time zone. So, to override these effects,
> we
> * use the first 50 time samples for initial system time setting.
> + * If the host_time_sync module parameter is set, we will use the host
> + time
> + * samples to adjust guest time after the first 50 samples.
> */
> static inline void adj_guesttime(u64 hosttime, u8 flags) {
> struct adj_time_work *wrk;
> static s32 scnt = 50;
> + static s32 sample_count;
>
> wrk = kmalloc(sizeof(struct adj_time_work), GFP_ATOMIC);
> if (wrk == NULL)
> @@ -214,6 +283,7 @@ static inline void adj_guesttime(u64 hosttime, u8 flags)
>
> wrk->host_time = hosttime;
> if ((flags & ICTIMESYNCFLAG_SYNC) != 0) {
> + wrk->forceSync = true;
> INIT_WORK(&wrk->work, hv_set_host_time);
> schedule_work(&wrk->work);
> return;
> @@ -221,10 +291,38 @@ static inline void adj_guesttime(u64 hosttime, u8
> flags)
>
> if ((flags & ICTIMESYNCFLAG_SAMPLE) != 0 && scnt > 0) {
> scnt--;
> + wrk->forceSync = true;
> INIT_WORK(&wrk->work, hv_set_host_time);
> schedule_work(&wrk->work);
> - } else
> - kfree(wrk);
> + return;
> + }
> +
> + if (host_time_sync) {
> + /*
> + * Use the Hyper-V time sample to adjust the guest time. The
> + * algorithm is: If the sample offsets exceeds 1 second, we
> + * directly set the clock to the server time. If the offset is
> + * less than 1ms, we ignore the time sample. Otherwise we
> adjust
> + * the clock.
> + */
> +
> + if ((flags & ICTIMESYNCFLAG_SAMPLE) != 0) {
> + if (sample_count < adj_interval) {
> + sample_count++;
> + goto cleanup;
> + }
> + /* reset the polling interval */
> + sample_count = 0;
> + wrk->forceSync = false;
> + INIT_WORK(&wrk->work, hv_set_host_time);
> + schedule_work(&wrk->work);
> + return;
> + }
> + }
> +
> +cleanup:
> + kfree(wrk);
> +
> }
>
> /*
> diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index
> ec1791f..381a1ca 100644
> --- a/kernel/time/timekeeping.c
> +++ b/kernel/time/timekeeping.c
> @@ -1786,6 +1786,7 @@ int do_adjtimex(struct timex *txc)
>
> return ret;
> }
> +EXPORT_SYMBOL(do_adjtimex);
>
> #ifdef CONFIG_NTP_PPS
> /**
> --
> 1.7.1