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| author | Richard Cochran <richardcochran@gmail.com> | 2014-12-21 19:47:06 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2014-12-30 18:29:27 -0500 |
| commit | 2eebdde6528a722fbf8e2cffcf7aa52cbb4c2de0 (patch) | |
| tree | c4b176d1e40eecb2caa00952eae95ecb2b2a046b /drivers/net/ethernet/mellanox | |
| parent | f25a30be359d0535fb1c7c1619cabb0ad17cfbf1 (diff) | |
| download | linux-2eebdde6528a722fbf8e2cffcf7aa52cbb4c2de0.tar.gz linux-2eebdde6528a722fbf8e2cffcf7aa52cbb4c2de0.tar.bz2 linux-2eebdde6528a722fbf8e2cffcf7aa52cbb4c2de0.zip | |
timecounter: keep track of accumulated fractional nanoseconds
The current timecounter implementation will drop a variable amount
of resolution, depending on the magnitude of the time delta. In
other words, reading the clock too often or too close to a time
stamp conversion will introduce errors into the time values. This
patch fixes the issue by introducing a fractional nanosecond field
that accumulates the low order bits.
Reported-by: Janusz Użycki <j.uzycki@elproma.com.pl>
Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/mellanox')
| -rw-r--r-- | drivers/net/ethernet/mellanox/mlx4/en_clock.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_clock.c b/drivers/net/ethernet/mellanox/mlx4/en_clock.c index df35d0e1b899..e9cce4f72b24 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c @@ -240,7 +240,7 @@ void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev) { struct mlx4_dev *dev = mdev->dev; unsigned long flags; - u64 ns; + u64 ns, zero = 0; rwlock_init(&mdev->clock_lock); @@ -265,7 +265,7 @@ void mlx4_en_init_timestamp(struct mlx4_en_dev *mdev) /* 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); + ns = cyclecounter_cyc2ns(&mdev->cycles, mdev->cycles.mask, zero, &zero); do_div(ns, NSEC_PER_SEC / 2 / HZ); mdev->overflow_period = ns; |