| Message ID | 1504893565-110166-10-git-send-email-bhanuprakash.bodireddy@intel.com |
|---|---|
| State | Rejected |
| Headers | show |
| Series | Rearrange structure members for memory efficiency. | expand |
On Fri, Sep 08, 2017 at 06:59:21PM +0100, Bhanuprakash Bodireddy wrote: > By reordering elements in dpif_flow_put structure, holes can be removed. > > Before: structure size: 80, sum holes: 8, cachelines:2 > After : structure size: 72, sum holes: 0, cachelines:2 > > Signed-off-by: Bhanuprakash Bodireddy <bhanuprakash.bodireddy@intel.com> Thanks for the patch. This is one case where I don't think the change is worth it. The structure is a little smaller, but this structure is generally on the stack and often part of union dpif_op, and I think that moving pmd_id to the beginning of the struct makes it look more important than it is. So, I'm going to skip this one.
diff --git a/lib/dpif.h b/lib/dpif.h index d9ded8b..bef7845 100644 --- a/lib/dpif.h +++ b/lib/dpif.h @@ -638,6 +638,7 @@ enum dpif_op_type { */ struct dpif_flow_put { /* Input. */ + unsigned pmd_id; /* Datapath poll mode driver id. */ enum dpif_flow_put_flags flags; /* DPIF_FP_*. */ const struct nlattr *key; /* Flow to put. */ size_t key_len; /* Length of 'key' in bytes. */ @@ -646,7 +647,6 @@ struct dpif_flow_put { const struct nlattr *actions; /* Actions to perform on flow. */ size_t actions_len; /* Length of 'actions' in bytes. */ const ovs_u128 *ufid; /* Optional unique flow identifier. */ - unsigned pmd_id; /* Datapath poll mode driver id. */ /* Output. */ struct dpif_flow_stats *stats; /* Optional flow statistics. */
By reordering elements in dpif_flow_put structure, holes can be removed. Before: structure size: 80, sum holes: 8, cachelines:2 After : structure size: 72, sum holes: 0, cachelines:2 Signed-off-by: Bhanuprakash Bodireddy <bhanuprakash.bodireddy@intel.com> --- lib/dpif.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)