Hi greg,
>On 09/08/2017 10:59 AM, Bhanuprakash Bodireddy wrote:
>> By reordering elements in dummy_packet_stream structure, sum holes
>
>Do you mean "the sum of the holes" can be reduced or do you mean "some
>holes"
>can be reduced?
In this patch series "sum of the holes" means, the sum/total of all the hole
bytes in the
respective structure. For example 'dummy_packet_stream' structure members are
aligned below way.
This structure has one hole comprising of 56 bytes.
struct dummy_packet_stream {
struct stream * stream; /* 0 8 */
====> 56 bytes holes.
struct dp_packet rxbuf; /* 64 704 */
struct ovs_list txq; /* 768 16 */
};
With the proposed change in this patch, the new alignment is as below
struct dummy_packet_stream {
struct stream * stream; /* 0 8 */
struct ovs_list txq; /* 8 16
*/
====> 40 bytes hole
struct dp_packet rxbuf; /* 64 704 */
};
For all the patches, the information is added in to the commit log that shows
the improvement with the proposed changes. As claimed, sum holes(bytes) are
reduced from 56 to 40 in case of this patch.
>> Before: structure size: 784, sum holes: 56, cachelines:13
>> After : structure size: 768, sum holes: 40, cachelines:12
>
>Same question through several of the other patches where you use the same
>language.
In few structures there are multiple holes and 'sum holes' adds hole bytes of
multiple holes
In those cases.
- Bhanuprakash.
>
>> can be reduced, thus saving a cache line.
>>
>> Before: structure size: 784, sum holes: 56, cachelines:13 After :
>> structure size: 768, sum holes: 40, cachelines:12
>>
>> Signed-off-by: Bhanuprakash Bodireddy
>> <[email protected]>
>> ---
>> lib/netdev-dummy.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/lib/netdev-dummy.c b/lib/netdev-dummy.c index
>> f731af1..d888c40 100644
>> --- a/lib/netdev-dummy.c
>> +++ b/lib/netdev-dummy.c
>> @@ -50,8 +50,8 @@ struct reconnect;
>>
>> struct dummy_packet_stream {
>> struct stream *stream;
>> - struct dp_packet rxbuf;
>> struct ovs_list txq;
>> + struct dp_packet rxbuf;
>> };
>>
>> enum dummy_packet_conn_type {
>>
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