> -----Original Message-----
> From: Ferruh Yigit <ferruh.yi...@intel.com>
> Sent: Wednesday, January 29, 2020 6:23 AM
> To: David Harton (dharton) <dhar...@cisco.com>; dev@dpdk.org
> Cc: wenzhuo...@intel.com; konstantin.anan...@intel.com;
> xiaolong...@intel.com; intel....@cisco.com
> Subject: Re: [dpdk-dev] [PATCH v2] net/ixgbevf: update VF_STAT macros to
> handle rollover
>
> On 1/26/2020 5:32 PM, David Harton wrote:
> > Added rollover logic to UPDATE_VF_STAT and UPDATE_VF_STAT_36BIT macros.
> >
> > Fixes: af75078fece3 ("first public release")
> > Cc: intel.com
> >
> > Signed-off-by: David Harton <dhar...@cisco.com>
> > ---
> > drivers/net/ixgbe/ixgbe_ethdev.c | 12 ++++++++++--
> > 1 file changed, 10 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/ixgbe/ixgbe_ethdev.c
> > b/drivers/net/ixgbe/ixgbe_ethdev.c
> > index 49285ce53..bc73ad195 100644
> > --- a/drivers/net/ixgbe/ixgbe_ethdev.c
> > +++ b/drivers/net/ixgbe/ixgbe_ethdev.c
> > @@ -385,7 +385,11 @@ static void ixgbe_l2_tunnel_conf(struct rte_eth_dev
> *dev);
> > #define UPDATE_VF_STAT(reg, last, cur) \
> > { \
> > uint32_t latest = IXGBE_READ_REG(hw, reg); \
> > - cur += (latest - last) & UINT_MAX; \
>
> Here since 'last' is 'u64', the 'UINT_MAX' is required, but overall this
> looks good, original code should be OK.
Agreed. As mentioned on the igbvf thread I've gone back to the developer for
justification.
Regards,
Dave
>
> > + if (latest >= last) \
> > + cur += (latest - last); \
> > + else \
> > + cur += ((latest + ((uint64_t)1 << 32)) - last); \
> > + cur &= UINT_MAX; \
> > last = latest; \
> > }
> >
> > @@ -394,7 +398,11 @@ static void ixgbe_l2_tunnel_conf(struct rte_eth_dev
> *dev);
> > u64 new_lsb = IXGBE_READ_REG(hw, lsb); \
> > u64 new_msb = IXGBE_READ_REG(hw, msb); \
> > u64 latest = ((new_msb << 32) | new_lsb); \
> > - cur += (0x1000000000LL + latest - last) & 0xFFFFFFFFFLL; \
> > + if (latest >= last) \
> > + cur += (latest - last); \
> > + else \
> > + cur += ((latest + ((u64)1 << 36)) - last); \
> > + cur &= 0xFFFFFFFFFLL; \
>
> For this case old and new implementation looks same to me.
>
> > last = latest; \
> > }
> >
> >
