[dpdk-dev] [PATCH] keepalive: fix keepalive state alignment

[Remy Horton]

On 22/01/2018 18:20, Andriy Berestovskyy wrote:
[..]
> On Fri, Jan 19, 2018 at 6:31 PM, Van Haaren, Harry
> <harry.van.haaren at intel.com> wrote:
>> These changes do reduce false-sharing however is there actually a
>> performance benefit? A lot of cache space will be taken up if each
>> core requires its own cache line, which will reduce performance
>> again.. it's a tradeoff.
[..]
> 2. The original code (prior e70a61ad50ab "keepalive: export states")
> had each element aligned to the cache line, not the whole array.

Aligning each flag element was the original intention, so I see no issue 
in restoring it. The monitoring core only reads the entries within 
state_flags for which the corresponding active_core is set, so 
ultimately the trade-off in cache line usage is one made by the 
application when it decides which cores need monitoring.

..Remy