From: Ferruh Yigit <ferruh.yigit@intel.com>
To: David Harton <dharton@cisco.com>, dev@dpdk.org
Cc: wenzhuo.lu@intel.com, konstantin.ananyev@intel.com,
xiaolong.ye@intel.com, intel.com@cisco.com
Subject: Re: [dpdk-dev] [PATCH v2] net/e1000: update UPDATE_VF_STAT to handle rollover
Date: Wed, 29 Jan 2020 10:10:05 +0000 [thread overview]
Message-ID: <558f34ae-e577-62ca-04e1-1097e6ee1abb@intel.com> (raw)
In-Reply-To: <20200126172548.23327-1-dharton@cisco.com>
On 1/26/2020 5:25 PM, David Harton wrote:
> Modified UPDATE_VF_STAT to properly handle rollover conditions.
>
> Fixes: d82170d27918 ("igb: add VF support")
> Cc: intel.com
>
> Signed-off-by: David Harton <dharton@cisco.com>
> ---
> drivers/net/e1000/igb_ethdev.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/e1000/igb_ethdev.c b/drivers/net/e1000/igb_ethdev.c
> index a3e30dbe5..825663267 100644
> --- a/drivers/net/e1000/igb_ethdev.c
> +++ b/drivers/net/e1000/igb_ethdev.c
> @@ -261,11 +261,15 @@ static int igb_filter_restore(struct rte_eth_dev *dev);
> /*
> * Define VF Stats MACRO for Non "cleared on read" register
> */
> -#define UPDATE_VF_STAT(reg, last, cur) \
> -{ \
> - u32 latest = E1000_READ_REG(hw, reg); \
> - cur += (latest - last) & UINT_MAX; \
Why this is wrong? Both 'latest' and 'last' are 'u32', so diff should be correct
'u32' value. And it is added to 'u64' 'cur' value. What I am missing?
> - last = latest; \
> +#define UPDATE_VF_STAT(reg, last, cur) \
> +{ \
> + u32 latest = E1000_READ_REG(hw, reg); \
> + if (latest >= last) \
> + cur += (latest - last); \
> + else \
> + cur += ((latest + ((uint64_t)1 << 32)) - last); \
> + cur &= UINT_MAX; \
Why & with UINT_MAX, won't this limit the value to 32bits which has 64bit storage?
> + last = latest; \
> }
>
> #define IGB_FC_PAUSE_TIME 0x0680
>
next prev parent reply other threads:[~2020-01-29 10:10 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-11 2:48 [dpdk-dev] [PATCH] " David Harton
2020-01-26 9:41 ` Ye Xiaolong
2020-01-26 17:25 ` [dpdk-dev] [PATCH v2] " David Harton
2020-01-29 7:53 ` Ye Xiaolong
2020-01-29 10:10 ` Ferruh Yigit [this message]
2020-01-29 17:56 ` David Harton (dharton)
2020-01-31 8:46 ` Ye Xiaolong
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