| Message ID | 1487892163.9415.111.camel@edumazet-glaptop3.roam.corp.google.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
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.
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.
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.
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.
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;