* [PATCH net] net/mlx4_en: fix overflow in mlx4_en_init_timestamp()
@ 2017-02-23 23:22 Eric Dumazet
2017-02-24 16:21 ` David Miller
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Eric Dumazet @ 2017-02-23 23:22 UTC (permalink / raw)
To: David Miller; +Cc: netdev, Eugenia Emantayev, Tariq Toukan
From: Eric Dumazet <edumazet@google.com>
The cited commit makes a great job of finding optimal shift/multiplier
values assuming a 10 seconds wrap around, but forgot to change the
overflow_period computation.
It overflows in cyclecounter_cyc2ns(), and the final result is 804 ms,
which is silly.
Lets simply use 5 seconds, no need to recompute this, given how it is
supposed to work.
Later, we will use a timer instead of a work queue, since the new RX
allocation schem will no longer need mlx4_en_recover_from_oom() and the
service_task firing every 250 ms.
Fixes: 31c128b66e5b ("net/mlx4_en: Choose time-stamping shift value according to HW frequency")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Tariq Toukan <tariqt@mellanox.com>
Cc: Eugenia Emantayev <eugenia@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx4/en_clock.c | 18 +++++++---------
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 1
2 files changed, 8 insertions(+), 11 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_clock.c b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
index e7b81a305469e64b97f68bc0e2bcb064b78f08fe..024788549c2569a13d3a07ebbde718cccf980a26 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
@@ -89,10 +89,17 @@ void mlx4_en_remove_timestamp(struct mlx4_en_dev *mdev)
}
}
+#define MLX4_EN_WRAP_AROUND_SEC 10UL
+/* By scheduling the overflow check every 5 seconds, we have a reasonably
+ * good chance we wont miss a wrap around.
+ * TOTO: Use a timer instead of a work queue to increase the guarantee.
+ */
+#define MLX4_EN_OVERFLOW_PERIOD (MLX4_EN_WRAP_AROUND_SEC * HZ / 2)
+
void mlx4_en_ptp_overflow_check(struct mlx4_en_dev *mdev)
{
bool timeout = time_is_before_jiffies(mdev->last_overflow_check +
- mdev->overflow_period);
+ MLX4_EN_OVERFLOW_PERIOD);
unsigned long flags;
if (timeout) {
@@ -237,7 +244,6 @@ static const struct ptp_clock_info mlx4_en_ptp_clock_info = {
.enable = mlx4_en_phc_enable,
};
-#define MLX4_EN_WRAP_AROUND_SEC 10ULL
/* This function calculates the max shift that enables the user range
* of MLX4_EN_WRAP_AROUND_SEC values in the cycles register.
@@ -258,7 +264,6 @@ void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev)
{
struct mlx4_dev *dev = mdev->dev;
unsigned long flags;
- u64 ns, zero = 0;
/* mlx4_en_init_timestamp is called for each netdev.
* mdev->ptp_clock is common for all ports, skip initialization if
@@ -282,13 +287,6 @@ void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev)
ktime_to_ns(ktime_get_real()));
write_sequnlock_irqrestore(&mdev->clock_lock, flags);
- /* Calculate period in seconds to call the overflow watchdog - to make
- * sure counter is checked at least once every wrap around.
- */
- ns = cyclecounter_cyc2ns(&mdev->cycles, mdev->cycles.mask, zero, &zero);
- do_div(ns, NSEC_PER_SEC / 2 / HZ);
- mdev->overflow_period = ns;
-
/* Configure the PHC */
mdev->ptp_clock_info = mlx4_en_ptp_clock_info;
snprintf(mdev->ptp_clock_info.name, 16, "mlx4 ptp");
diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index 4941b692e9479bc7800e92f9bfb13baf3ff7d0d4..3629ce11a68b9dec5c1659539bdc6f2c11114e35 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -430,7 +430,6 @@ struct mlx4_en_dev {
seqlock_t clock_lock;
struct timecounter clock;
unsigned long last_overflow_check;
- unsigned long overflow_period;
struct ptp_clock *ptp_clock;
struct ptp_clock_info ptp_clock_info;
struct notifier_block nb;
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH net] net/mlx4_en: fix overflow in mlx4_en_init_timestamp()
2017-02-23 23:22 [PATCH net] net/mlx4_en: fix overflow in mlx4_en_init_timestamp() Eric Dumazet
@ 2017-02-24 16:21 ` David Miller
2017-02-25 16:11 ` Or Gerlitz
2017-02-26 17:28 ` Tariq Toukan
2017-02-26 20:45 ` David Miller
2 siblings, 1 reply; 5+ messages in thread
From: David Miller @ 2017-02-24 16:21 UTC (permalink / raw)
To: eric.dumazet; +Cc: netdev, eugenia, tariqt
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 23 Feb 2017 15:22:43 -0800
> From: Eric Dumazet <edumazet@google.com>
>
> The cited commit makes a great job of finding optimal shift/multiplier
> values assuming a 10 seconds wrap around, but forgot to change the
> overflow_period computation.
>
> It overflows in cyclecounter_cyc2ns(), and the final result is 804 ms,
> which is silly.
>
> Lets simply use 5 seconds, no need to recompute this, given how it is
> supposed to work.
>
> Later, we will use a timer instead of a work queue, since the new RX
> allocation schem will no longer need mlx4_en_recover_from_oom() and the
> service_task firing every 250 ms.
>
> Fixes: 31c128b66e5b ("net/mlx4_en: Choose time-stamping shift value according to HW frequency")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Tariq please review.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net] net/mlx4_en: fix overflow in mlx4_en_init_timestamp()
2017-02-24 16:21 ` David Miller
@ 2017-02-25 16:11 ` Or Gerlitz
0 siblings, 0 replies; 5+ messages in thread
From: Or Gerlitz @ 2017-02-25 16:11 UTC (permalink / raw)
To: David Miller
Cc: Eric Dumazet, Linux Netdev List, Eugenia Emantayev, Tariq Toukan
On Fri, Feb 24, 2017 at 6:21 PM, David Miller <davem@davemloft.net> wrote:
> From: Eric Dumazet <eric.dumazet@gmail.com>
> Date: Thu, 23 Feb 2017
> Tariq please review.
Dave,
Just to re-iterate what we wrote here couple of time, the IL WW is
Sun-Thu on GMT+2 hours and hence this patch was sent when the
developers/maintainer are into weekend mode.
Or.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net] net/mlx4_en: fix overflow in mlx4_en_init_timestamp()
2017-02-23 23:22 [PATCH net] net/mlx4_en: fix overflow in mlx4_en_init_timestamp() Eric Dumazet
2017-02-24 16:21 ` David Miller
@ 2017-02-26 17:28 ` Tariq Toukan
2017-02-26 20:45 ` David Miller
2 siblings, 0 replies; 5+ messages in thread
From: Tariq Toukan @ 2017-02-26 17:28 UTC (permalink / raw)
To: Eric Dumazet, David Miller; +Cc: netdev, Eugenia Emantayev, Tariq Toukan
On 24/02/2017 1:22 AM, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> The cited commit makes a great job of finding optimal shift/multiplier
> values assuming a 10 seconds wrap around, but forgot to change the
> overflow_period computation.
>
> It overflows in cyclecounter_cyc2ns(), and the final result is 804 ms,
> which is silly.
>
> Lets simply use 5 seconds, no need to recompute this, given how it is
> supposed to work.
>
> Later, we will use a timer instead of a work queue, since the new RX
> allocation schem will no longer need mlx4_en_recover_from_oom() and the
> service_task firing every 250 ms.
>
> Fixes: 31c128b66e5b ("net/mlx4_en: Choose time-stamping shift value according to HW frequency")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Tariq Toukan <tariqt@mellanox.com>
> Cc: Eugenia Emantayev <eugenia@mellanox.com>
> ---
> drivers/net/ethernet/mellanox/mlx4/en_clock.c | 18 +++++++---------
> drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 1
> 2 files changed, 8 insertions(+), 11 deletions(-)
>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
Thanks for your patch.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net] net/mlx4_en: fix overflow in mlx4_en_init_timestamp()
2017-02-23 23:22 [PATCH net] net/mlx4_en: fix overflow in mlx4_en_init_timestamp() Eric Dumazet
2017-02-24 16:21 ` David Miller
2017-02-26 17:28 ` Tariq Toukan
@ 2017-02-26 20:45 ` David Miller
2 siblings, 0 replies; 5+ messages in thread
From: David Miller @ 2017-02-26 20:45 UTC (permalink / raw)
To: eric.dumazet; +Cc: netdev, eugenia, tariqt
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 23 Feb 2017 15:22:43 -0800
> From: Eric Dumazet <edumazet@google.com>
>
> The cited commit makes a great job of finding optimal shift/multiplier
> values assuming a 10 seconds wrap around, but forgot to change the
> overflow_period computation.
>
> It overflows in cyclecounter_cyc2ns(), and the final result is 804 ms,
> which is silly.
>
> Lets simply use 5 seconds, no need to recompute this, given how it is
> supposed to work.
>
> Later, we will use a timer instead of a work queue, since the new RX
> allocation schem will no longer need mlx4_en_recover_from_oom() and the
> service_task firing every 250 ms.
>
> Fixes: 31c128b66e5b ("net/mlx4_en: Choose time-stamping shift value according to HW frequency")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Applied, thanks.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2017-02-26 20:45 UTC | newest]
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2017-02-23 23:22 [PATCH net] net/mlx4_en: fix overflow in mlx4_en_init_timestamp() Eric Dumazet
2017-02-24 16:21 ` David Miller
2017-02-25 16:11 ` Or Gerlitz
2017-02-26 17:28 ` Tariq Toukan
2017-02-26 20:45 ` David Miller
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