[ovs-dev] [PATCH net-next v2] openvswitch: Make 100 percents packets sampled when sampling rate is 1.

Pravin Shelar pshelar at nicira.com
Tue Aug 4 22:00:28 UTC 2015


On Mon, Aug 3, 2015 at 9:07 PM, Wenyu Zhang <wenyuz at vmware.com> wrote:
> When sampling rate is 1, the sampling probability is UINT32_MAX. The packet
> should be sampled even the prandom_u32() generate the number of UINT32_MAX.
> And none packet need be sampled when the probability is 0.
>
> Signed-off-by: Wenyu Zhang <wenyuz at vmware.com>

Patch looks good, I have following minor comments.

> ---
>  net/openvswitch/actions.c |    4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
> index cf04c2f..c81bcf5 100644
> --- a/net/openvswitch/actions.c
> +++ b/net/openvswitch/actions.c
> @@ -669,9 +669,11 @@ static int sample(struct datapath *dp, struct sk_buff *skb,
>
>         for (a = nla_data(attr), rem = nla_len(attr); rem > 0;
>                  a = nla_next(a, &rem)) {
> +               uint32_t probability;
>                 switch (nla_type(a)) {
There should be blank line after variable definitions.

>                 case OVS_SAMPLE_ATTR_PROBABILITY:
> -                       if (prandom_u32() >= nla_get_u32(a))
> +                       probability = nla_get_u32(a);
> +                       if (!probability || prandom_u32() > probability)
>                                 return 0;
>                         break;
>
I got following warning on checkpatch.pl

./scripts/checkpatch.pl
0001-openvswitch-Make-100-percents-packets-sampled-when-s.patch

CHECK: Prefer kernel type 'u32' over 'uint32_t'

#24: FILE: net/openvswitch/actions.c:672:

+ uint32_t probability;


total: 0 errors, 0 warnings, 1 checks, 12 lines checked



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