[ovs-dev] [PATCH v2 2/3] ofproto-dpif: Improve dp_hash selection method for select groups

Ben Pfaff blp at ovn.org
Tue Apr 17 20:03:17 UTC 2018


On Mon, Apr 16, 2018 at 04:26:27PM +0200, Jan Scheurich wrote:
> The current implementation of the "dp_hash" selection method suffers
> from two deficiences: 1. The hash mask and hence the number of dp_hash
> values is just large enough to cover the number of group buckets, but
> does not consider the case that buckets have different weights. 2. The
> xlate-time selection of best bucket from the masked dp_hash value often
> results in bucket load distributions that are quite different from the
> bucket weights because the number of available masked dp_hash values
> is too small (2-6 bits compared to 32 bits of a full hash in the default
> hash selection method).

Clang gives me the following errors:

    ../ofproto/ofproto-dpif.c:4792:32: error: unknown warning group '-Wmaybe-uninitialized', ignored [-Werror,-Wunknown-pragmas]
    ../ofproto/ofproto-dpif.c:4814:33: error: initializing 'struct ofputil_group_props *' with an expression of type 'const struct ofputil_group_props *' discards qualifiers [-Werror,-Wincompatible-pointer-types-discards-qualifiers]

"sparse" gives me the following errors:

    ../ofproto/ofproto-dpif.c:4742:24: error: Variable length array is used.
    ../ofproto/ofproto-dpif.c:4814:42: error: incorrect type in initializer (different modifiers)
    ../ofproto/ofproto-dpif.c:4814:42:    expected struct ofputil_group_props *props
    ../ofproto/ofproto-dpif.c:4814:42:    got struct ofputil_group_props const *<noident>

Thanks,

Ben.


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