* [PATCH v2 net] igb: shorten maximum PHC timecounter update interval
@ 2018-10-26 17:13 ` Miroslav Lichvar
0 siblings, 0 replies; 8+ messages in thread
From: Miroslav Lichvar @ 2018-10-26 17:13 UTC (permalink / raw)
To: netdev
Cc: intel-wired-lan, Miroslav Lichvar, Jacob Keller, Richard Cochran,
Thomas Gleixner
The timecounter needs to be updated at least once per ~550 seconds in
order to avoid a 40-bit SYSTIM timestamp to be misinterpreted as an old
timestamp.
Since commit 500462a9de65 ("timers: Switch to a non-cascading wheel"),
scheduling of delayed work seems to be less accurate and a requested
delay of 540 seconds may actually be longer than 550 seconds. Also, the
PHC may be adjusted to run up to 6% faster than real time and the system
clock up to 10% slower. Shorten the delay to 360 seconds to be sure the
timecounter is updated in time.
This fixes an issue with HW timestamps on 82580/I350/I354 being off by
~1100 seconds for few seconds every ~9 minutes.
Cc: Jacob Keller <jacob.e.keller@intel.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
---
drivers/net/ethernet/intel/igb/igb_ptp.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c
index 9f4d700e09df..2b95dc9c7a6a 100644
--- a/drivers/net/ethernet/intel/igb/igb_ptp.c
+++ b/drivers/net/ethernet/intel/igb/igb_ptp.c
@@ -51,9 +51,17 @@
*
* The 40 bit 82580 SYSTIM overflows every
* 2^40 * 10^-9 / 60 = 18.3 minutes.
+ *
+ * SYSTIM is converted to real time using a timecounter. As
+ * timecounter_cyc2time() allows old timestamps, the timecounter needs
+ * to be updated at least once per half of the SYSTIM interval.
+ * Scheduling of delayed work is not very accurate, and also the NIC
+ * clock can be adjusted to run up to 6% faster and the system clock
+ * up to 10% slower, so we aim for 6 minutes to be sure the actual
+ * interval in the NIC time is shorter than 9.16 minutes.
*/
-#define IGB_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 9)
+#define IGB_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 6)
#define IGB_PTP_TX_TIMEOUT (HZ * 15)
#define INCPERIOD_82576 BIT(E1000_TIMINCA_16NS_SHIFT)
#define INCVALUE_82576_MASK GENMASK(E1000_TIMINCA_16NS_SHIFT - 1, 0)
--
2.17.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [Intel-wired-lan] [PATCH v2 net] igb: shorten maximum PHC timecounter update interval
@ 2018-10-26 17:13 ` Miroslav Lichvar
0 siblings, 0 replies; 8+ messages in thread
From: Miroslav Lichvar @ 2018-10-26 17:13 UTC (permalink / raw)
To: intel-wired-lan
The timecounter needs to be updated at least once per ~550 seconds in
order to avoid a 40-bit SYSTIM timestamp to be misinterpreted as an old
timestamp.
Since commit 500462a9de65 ("timers: Switch to a non-cascading wheel"),
scheduling of delayed work seems to be less accurate and a requested
delay of 540 seconds may actually be longer than 550 seconds. Also, the
PHC may be adjusted to run up to 6% faster than real time and the system
clock up to 10% slower. Shorten the delay to 360 seconds to be sure the
timecounter is updated in time.
This fixes an issue with HW timestamps on 82580/I350/I354 being off by
~1100 seconds for few seconds every ~9 minutes.
Cc: Jacob Keller <jacob.e.keller@intel.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
---
drivers/net/ethernet/intel/igb/igb_ptp.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c b/drivers/net/ethernet/intel/igb/igb_ptp.c
index 9f4d700e09df..2b95dc9c7a6a 100644
--- a/drivers/net/ethernet/intel/igb/igb_ptp.c
+++ b/drivers/net/ethernet/intel/igb/igb_ptp.c
@@ -51,9 +51,17 @@
*
* The 40 bit 82580 SYSTIM overflows every
* 2^40 * 10^-9 / 60 = 18.3 minutes.
+ *
+ * SYSTIM is converted to real time using a timecounter. As
+ * timecounter_cyc2time() allows old timestamps, the timecounter needs
+ * to be updated at least once per half of the SYSTIM interval.
+ * Scheduling of delayed work is not very accurate, and also the NIC
+ * clock can be adjusted to run up to 6% faster and the system clock
+ * up to 10% slower, so we aim for 6 minutes to be sure the actual
+ * interval in the NIC time is shorter than 9.16 minutes.
*/
-#define IGB_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 9)
+#define IGB_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 6)
#define IGB_PTP_TX_TIMEOUT (HZ * 15)
#define INCPERIOD_82576 BIT(E1000_TIMINCA_16NS_SHIFT)
#define INCVALUE_82576_MASK GENMASK(E1000_TIMINCA_16NS_SHIFT - 1, 0)
--
2.17.2
^ permalink raw reply related [flat|nested] 8+ messages in thread
* RE: [PATCH v2 net] igb: shorten maximum PHC timecounter update interval
2018-10-26 17:13 ` [Intel-wired-lan] " Miroslav Lichvar
@ 2018-10-26 17:20 ` Keller, Jacob E
-1 siblings, 0 replies; 8+ messages in thread
From: Keller, Jacob E @ 2018-10-26 17:20 UTC (permalink / raw)
To: Miroslav Lichvar, netdev
Cc: intel-wired-lan, Richard Cochran, Thomas Gleixner
> -----Original Message-----
> From: Miroslav Lichvar [mailto:mlichvar@redhat.com]
> Sent: Friday, October 26, 2018 10:13 AM
> To: netdev@vger.kernel.org
> Cc: intel-wired-lan@lists.osuosl.org; Miroslav Lichvar <mlichvar@redhat.com>;
> Keller, Jacob E <jacob.e.keller@intel.com>; Richard Cochran
> <richardcochran@gmail.com>; Thomas Gleixner <tglx@linutronix.de>
> Subject: [PATCH v2 net] igb: shorten maximum PHC timecounter update interval
>
> The timecounter needs to be updated at least once per ~550 seconds in
> order to avoid a 40-bit SYSTIM timestamp to be misinterpreted as an old
> timestamp.
>
> Since commit 500462a9de65 ("timers: Switch to a non-cascading wheel"),
> scheduling of delayed work seems to be less accurate and a requested
> delay of 540 seconds may actually be longer than 550 seconds. Also, the
> PHC may be adjusted to run up to 6% faster than real time and the system
> clock up to 10% slower. Shorten the delay to 360 seconds to be sure the
> timecounter is updated in time.
>
> This fixes an issue with HW timestamps on 82580/I350/I354 being off by
> ~1100 seconds for few seconds every ~9 minutes.
>
Acked-by: Jacob Keller <jacob.e.keller@intel.com>
> Cc: Jacob Keller <jacob.e.keller@intel.com>
> Cc: Richard Cochran <richardcochran@gmail.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
> ---
> drivers/net/ethernet/intel/igb/igb_ptp.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c
> b/drivers/net/ethernet/intel/igb/igb_ptp.c
> index 9f4d700e09df..2b95dc9c7a6a 100644
> --- a/drivers/net/ethernet/intel/igb/igb_ptp.c
> +++ b/drivers/net/ethernet/intel/igb/igb_ptp.c
> @@ -51,9 +51,17 @@
> *
> * The 40 bit 82580 SYSTIM overflows every
> * 2^40 * 10^-9 / 60 = 18.3 minutes.
> + *
> + * SYSTIM is converted to real time using a timecounter. As
> + * timecounter_cyc2time() allows old timestamps, the timecounter needs
> + * to be updated at least once per half of the SYSTIM interval.
> + * Scheduling of delayed work is not very accurate, and also the NIC
> + * clock can be adjusted to run up to 6% faster and the system clock
> + * up to 10% slower, so we aim for 6 minutes to be sure the actual
> + * interval in the NIC time is shorter than 9.16 minutes.
> */
>
> -#define IGB_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 9)
> +#define IGB_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 6)
> #define IGB_PTP_TX_TIMEOUT (HZ * 15)
> #define INCPERIOD_82576 BIT(E1000_TIMINCA_16NS_SHIFT)
> #define INCVALUE_82576_MASK
> GENMASK(E1000_TIMINCA_16NS_SHIFT - 1, 0)
> --
> 2.17.2
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Intel-wired-lan] [PATCH v2 net] igb: shorten maximum PHC timecounter update interval
@ 2018-10-26 17:20 ` Keller, Jacob E
0 siblings, 0 replies; 8+ messages in thread
From: Keller, Jacob E @ 2018-10-26 17:20 UTC (permalink / raw)
To: intel-wired-lan
> -----Original Message-----
> From: Miroslav Lichvar [mailto:mlichvar at redhat.com]
> Sent: Friday, October 26, 2018 10:13 AM
> To: netdev at vger.kernel.org
> Cc: intel-wired-lan at lists.osuosl.org; Miroslav Lichvar <mlichvar@redhat.com>;
> Keller, Jacob E <jacob.e.keller@intel.com>; Richard Cochran
> <richardcochran@gmail.com>; Thomas Gleixner <tglx@linutronix.de>
> Subject: [PATCH v2 net] igb: shorten maximum PHC timecounter update interval
>
> The timecounter needs to be updated at least once per ~550 seconds in
> order to avoid a 40-bit SYSTIM timestamp to be misinterpreted as an old
> timestamp.
>
> Since commit 500462a9de65 ("timers: Switch to a non-cascading wheel"),
> scheduling of delayed work seems to be less accurate and a requested
> delay of 540 seconds may actually be longer than 550 seconds. Also, the
> PHC may be adjusted to run up to 6% faster than real time and the system
> clock up to 10% slower. Shorten the delay to 360 seconds to be sure the
> timecounter is updated in time.
>
> This fixes an issue with HW timestamps on 82580/I350/I354 being off by
> ~1100 seconds for few seconds every ~9 minutes.
>
Acked-by: Jacob Keller <jacob.e.keller@intel.com>
> Cc: Jacob Keller <jacob.e.keller@intel.com>
> Cc: Richard Cochran <richardcochran@gmail.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
> ---
> drivers/net/ethernet/intel/igb/igb_ptp.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c
> b/drivers/net/ethernet/intel/igb/igb_ptp.c
> index 9f4d700e09df..2b95dc9c7a6a 100644
> --- a/drivers/net/ethernet/intel/igb/igb_ptp.c
> +++ b/drivers/net/ethernet/intel/igb/igb_ptp.c
> @@ -51,9 +51,17 @@
> *
> * The 40 bit 82580 SYSTIM overflows every
> * 2^40 * 10^-9 / 60 = 18.3 minutes.
> + *
> + * SYSTIM is converted to real time using a timecounter. As
> + * timecounter_cyc2time() allows old timestamps, the timecounter needs
> + * to be updated at least once per half of the SYSTIM interval.
> + * Scheduling of delayed work is not very accurate, and also the NIC
> + * clock can be adjusted to run up to 6% faster and the system clock
> + * up to 10% slower, so we aim for 6 minutes to be sure the actual
> + * interval in the NIC time is shorter than 9.16 minutes.
> */
>
> -#define IGB_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 9)
> +#define IGB_SYSTIM_OVERFLOW_PERIOD (HZ * 60 * 6)
> #define IGB_PTP_TX_TIMEOUT (HZ * 15)
> #define INCPERIOD_82576 BIT(E1000_TIMINCA_16NS_SHIFT)
> #define INCVALUE_82576_MASK
> GENMASK(E1000_TIMINCA_16NS_SHIFT - 1, 0)
> --
> 2.17.2
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 net] igb: shorten maximum PHC timecounter update interval
2018-10-26 17:13 ` [Intel-wired-lan] " Miroslav Lichvar
@ 2018-10-31 2:30 ` Richard Cochran
-1 siblings, 0 replies; 8+ messages in thread
From: Richard Cochran @ 2018-10-31 2:30 UTC (permalink / raw)
To: Miroslav Lichvar; +Cc: netdev, intel-wired-lan, Jacob Keller, Thomas Gleixner
On Fri, Oct 26, 2018 at 07:13:00PM +0200, Miroslav Lichvar wrote:
> The timecounter needs to be updated at least once per ~550 seconds in
> order to avoid a 40-bit SYSTIM timestamp to be misinterpreted as an old
> timestamp.
>
> Since commit 500462a9de65 ("timers: Switch to a non-cascading wheel"),
> scheduling of delayed work seems to be less accurate and a requested
> delay of 540 seconds may actually be longer than 550 seconds. Also, the
> PHC may be adjusted to run up to 6% faster than real time and the system
> clock up to 10% slower. Shorten the delay to 360 seconds to be sure the
> timecounter is updated in time.
>
> This fixes an issue with HW timestamps on 82580/I350/I354 being off by
> ~1100 seconds for few seconds every ~9 minutes.
Acked-by: Richard Cochran <richardcochran@gmail.com>
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Intel-wired-lan] [PATCH v2 net] igb: shorten maximum PHC timecounter update interval
@ 2018-10-31 2:30 ` Richard Cochran
0 siblings, 0 replies; 8+ messages in thread
From: Richard Cochran @ 2018-10-31 2:30 UTC (permalink / raw)
To: intel-wired-lan
On Fri, Oct 26, 2018 at 07:13:00PM +0200, Miroslav Lichvar wrote:
> The timecounter needs to be updated at least once per ~550 seconds in
> order to avoid a 40-bit SYSTIM timestamp to be misinterpreted as an old
> timestamp.
>
> Since commit 500462a9de65 ("timers: Switch to a non-cascading wheel"),
> scheduling of delayed work seems to be less accurate and a requested
> delay of 540 seconds may actually be longer than 550 seconds. Also, the
> PHC may be adjusted to run up to 6% faster than real time and the system
> clock up to 10% slower. Shorten the delay to 360 seconds to be sure the
> timecounter is updated in time.
>
> This fixes an issue with HW timestamps on 82580/I350/I354 being off by
> ~1100 seconds for few seconds every ~9 minutes.
Acked-by: Richard Cochran <richardcochran@gmail.com>
^ permalink raw reply [flat|nested] 8+ messages in thread
* RE: [Intel-wired-lan] [PATCH v2 net] igb: shorten maximum PHC timecounter update interval
2018-10-26 17:13 ` [Intel-wired-lan] " Miroslav Lichvar
@ 2018-11-03 1:06 ` Brown, Aaron F
-1 siblings, 0 replies; 8+ messages in thread
From: Brown, Aaron F @ 2018-11-03 1:06 UTC (permalink / raw)
To: Miroslav Lichvar, netdev
Cc: intel-wired-lan, Richard Cochran, Thomas Gleixner
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces@osuosl.org] On
> Behalf Of Miroslav Lichvar
> Sent: Friday, October 26, 2018 10:13 AM
> To: netdev@vger.kernel.org
> Cc: intel-wired-lan@lists.osuosl.org; Richard Cochran
> <richardcochran@gmail.com>; Thomas Gleixner <tglx@linutronix.de>
> Subject: [Intel-wired-lan] [PATCH v2 net] igb: shorten maximum PHC
> timecounter update interval
>
> The timecounter needs to be updated at least once per ~550 seconds in
> order to avoid a 40-bit SYSTIM timestamp to be misinterpreted as an old
> timestamp.
>
> Since commit 500462a9de65 ("timers: Switch to a non-cascading wheel"),
> scheduling of delayed work seems to be less accurate and a requested
> delay of 540 seconds may actually be longer than 550 seconds. Also, the
> PHC may be adjusted to run up to 6% faster than real time and the system
> clock up to 10% slower. Shorten the delay to 360 seconds to be sure the
> timecounter is updated in time.
>
> This fixes an issue with HW timestamps on 82580/I350/I354 being off by
> ~1100 seconds for few seconds every ~9 minutes.
>
> Cc: Jacob Keller <jacob.e.keller@intel.com>
> Cc: Richard Cochran <richardcochran@gmail.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
> ---
> drivers/net/ethernet/intel/igb/igb_ptp.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Intel-wired-lan] [PATCH v2 net] igb: shorten maximum PHC timecounter update interval
@ 2018-11-03 1:06 ` Brown, Aaron F
0 siblings, 0 replies; 8+ messages in thread
From: Brown, Aaron F @ 2018-11-03 1:06 UTC (permalink / raw)
To: intel-wired-lan
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces at osuosl.org] On
> Behalf Of Miroslav Lichvar
> Sent: Friday, October 26, 2018 10:13 AM
> To: netdev at vger.kernel.org
> Cc: intel-wired-lan at lists.osuosl.org; Richard Cochran
> <richardcochran@gmail.com>; Thomas Gleixner <tglx@linutronix.de>
> Subject: [Intel-wired-lan] [PATCH v2 net] igb: shorten maximum PHC
> timecounter update interval
>
> The timecounter needs to be updated at least once per ~550 seconds in
> order to avoid a 40-bit SYSTIM timestamp to be misinterpreted as an old
> timestamp.
>
> Since commit 500462a9de65 ("timers: Switch to a non-cascading wheel"),
> scheduling of delayed work seems to be less accurate and a requested
> delay of 540 seconds may actually be longer than 550 seconds. Also, the
> PHC may be adjusted to run up to 6% faster than real time and the system
> clock up to 10% slower. Shorten the delay to 360 seconds to be sure the
> timecounter is updated in time.
>
> This fixes an issue with HW timestamps on 82580/I350/I354 being off by
> ~1100 seconds for few seconds every ~9 minutes.
>
> Cc: Jacob Keller <jacob.e.keller@intel.com>
> Cc: Richard Cochran <richardcochran@gmail.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
> ---
> drivers/net/ethernet/intel/igb/igb_ptp.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2018-11-03 10:15 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-10-26 17:13 [PATCH v2 net] igb: shorten maximum PHC timecounter update interval Miroslav Lichvar
2018-10-26 17:13 ` [Intel-wired-lan] " Miroslav Lichvar
2018-10-26 17:20 ` Keller, Jacob E
2018-10-26 17:20 ` [Intel-wired-lan] " Keller, Jacob E
2018-10-31 2:30 ` Richard Cochran
2018-10-31 2:30 ` [Intel-wired-lan] " Richard Cochran
2018-11-03 1:06 ` Brown, Aaron F
2018-11-03 1:06 ` Brown, Aaron F
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