diff mbox series

net/mlx5: fix Committed Bucket Size calculation

Message ID 20220207132840.929116-1-akozyrev@nvidia.com (mailing list archive)
State Accepted, archived
Delegated to: Raslan Darawsheh
Headers
Series net/mlx5: fix Committed Bucket Size calculation |

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ci/checkpatch success coding style OK
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ci/intel-Testing success Testing PASS
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ci/iol-aarch64-unit-testing success Testing PASS
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ci/iol-abi-testing success Testing PASS
ci/iol-x86_64-unit-testing success Testing PASS

Commit Message

Alexander Kozyrev Feb. 7, 2022, 1:28 p.m. UTC 
  Committed Bucket Size calculation tries to fit into 8-bit wide
mantissa field by setting 256 as a maximum value for it.
To compensate for this increase in the mantissa value the exponent
value has to be reduced by 8. But it gives a negative exponent
value for CBS less than 128. And negative exponent value is not
supported by the NIC. Adjust CSB calculation only for values
bigger than 128 to allow both small and big bucket sizes.

Fixes: 3bd26b23cef ("net/mlx5: support meter profile operations")
Cc: stable@dpdk.org

Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
---
 drivers/net/mlx5/mlx5_flow_meter.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Comments

Raslan Darawsheh Feb. 9, 2022, 8:53 a.m. UTC | #1 
Hi,

> -----Original Message-----
> From: Alexander Kozyrev <akozyrev@nvidia.com>
> Sent: Monday, February 7, 2022 3:29 PM
> To: dev@dpdk.org
> Cc: stable@dpdk.org; Raslan Darawsheh <rasland@nvidia.com>; Slava
> Ovsiienko <viacheslavo@nvidia.com>; Matan Azrad <matan@nvidia.com>;
> Suanming Mou <suanmingm@nvidia.com>
> Subject: [PATCH] net/mlx5: fix Committed Bucket Size calculation
> 
> Committed Bucket Size calculation tries to fit into 8-bit wide
> mantissa field by setting 256 as a maximum value for it.
> To compensate for this increase in the mantissa value the exponent
> value has to be reduced by 8. But it gives a negative exponent
> value for CBS less than 128. And negative exponent value is not
> supported by the NIC. Adjust CSB calculation only for values
> bigger than 128 to allow both small and big bucket sizes.
> 
> Fixes: 3bd26b23cef ("net/mlx5: support meter profile operations")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
> Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>

Patch applied to next-net-mlx,

Kindest regards,
Raslan Darawsheh
diff mbox series

Patch

diff --git a/drivers/net/mlx5/mlx5_flow_meter.c b/drivers/net/mlx5/mlx5_flow_meter.c
index 0dc7fbfb32..d0f8bcd100 100644
--- a/drivers/net/mlx5/mlx5_flow_meter.c
+++ b/drivers/net/mlx5/mlx5_flow_meter.c
@@ -295,8 +295,10 @@  mlx5_flow_meter_xbs_man_exp_calc(uint64_t xbs, uint8_t *man, uint8_t *exp)
 	}
 	/* xbs = xbs_mantissa * 2^xbs_exponent */
 	_man = frexp(xbs, &_exp);
-	_man = _man * pow(2, MLX5_MAN_WIDTH);
-	_exp = _exp - MLX5_MAN_WIDTH;
+	if (_exp >= MLX5_MAN_WIDTH) {
+		_man = _man * pow(2, MLX5_MAN_WIDTH);
+		_exp = _exp - MLX5_MAN_WIDTH;
+	}
 	*man = (uint8_t)ceil(_man);
 	*exp = _exp;
 }