On Mon, Dec 04, 2017 at 08:16:46PM +0000, Bhanuprakash Bodireddy wrote: > This commit introduces prefetch variants by using the GCC built-in > prefetch function. > > The prefetch variants gives the user better control on designing data > caching strategy in order to increase cache efficiency and minimize > cache pollution. Data reference patterns here can be classified in to > > - Non-temporal(NT) - Data that is referenced once and not reused in > immediate future. > - Temporal - Data will be used again soon. > > The Macro variants can be used where there are > - Predictable memory access patterns. > - Execution pipeline can stall if data isn't available. > - Time consuming loops. > > For example: > > OVS_PREFETCH_CACHE(addr, OPCH_LTR) > - OPCH_LTR : OVS PREFETCH CACHE HINT-LOW TEMPORAL READ. > - __builtin_prefetch(addr, 0, 1) > - Prefetch data in to L3 cache for readonly purpose. > > OVS_PREFETCH_CACHE(addr, OPCH_HTW) > - OPCH_HTW : OVS PREFETCH CACHE HINT-HIGH TEMPORAL WRITE. > - __builtin_prefetch(addr, 1, 3) > - Prefetch data in to all caches in anticipation of write. In doing > so it invalidates other cached copies so as to gain 'exclusive' > access. > > OVS_PREFETCH(addr) > - OPCH_HTR : OVS PREFETCH CACHE HINT-HIGH TEMPORAL READ. > - __builtin_prefetch(addr, 0, 3) > - Prefetch data in to all caches in anticipation of read and that > data will be used again soon (HTR - High Temporal Read). > > Signed-off-by: Bhanuprakash Bodireddy <bhanuprakash.bodire...@intel.com>
The information in this commit message seems like it could also be useful as part of a code comment. I didn't review the details of the patch. I will leave that for others. _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
