On 2024-08-27 17:10, Vipin Varghese wrote:
As core density continues to increase, chiplet-based
core packing has become a key trend. In AMD SoC EPYC
architectures, core complexes within the same chiplet
share a Last-Level Cache (LLC). By packing logical cores
within the same LLC, we can enhance pipeline processing
stages due to reduced latency and improved data locality.
To leverage these benefits, DPDK libraries and examples
can utilize localized lcores. This approach ensures more
consistent latencies by minimizing the dispersion of lcores
across different chiplet complexes and enhances packet
processing by ensuring that data for subsequent pipeline
stages is likely to reside within the LLC.
We shouldn't have a separate CPU/cache hierarchy API instead?
Could potentially be built on the 'hwloc' library.
I much agree cache/core topology may be of interest of the application
(or a work scheduler, like a DPDK event device), but it's not limited to
LLC. It may well be worthwhile to care about which cores shares L2
cache, for example. Not sure the RTE_LCORE_FOREACH_* approach scales.
< Function: Purpose >
---------------------
- rte_get_llc_first_lcores: Retrieves all the first lcores in the shared LLC.
- rte_get_llc_lcore: Retrieves all lcores that share the LLC.
- rte_get_llc_n_lcore: Retrieves the first n or skips the first n lcores in
the shared LLC.
< MACRO: Purpose >
------------------
RTE_LCORE_FOREACH_LLC_FIRST: iterates through all first lcore from each LLC.
RTE_LCORE_FOREACH_LLC_FIRST_WORKER: iterates through all first worker lcore
from each LLC.
RTE_LCORE_FOREACH_LLC_WORKER: iterates lcores from LLC based on hint (lcore id).
RTE_LCORE_FOREACH_LLC_SKIP_FIRST_WORKER: iterates lcores from LLC while
skipping first worker.
RTE_LCORE_FOREACH_LLC_FIRST_N_WORKER: iterates through `n` lcores from each LLC.
RTE_LCORE_FOREACH_LLC_SKIP_N_WORKER: skip first `n` lcores, then iterates
through reaming lcores in each LLC.
Vipin Varghese (2):
eal: add llc aware functions
eal/lcore: add llc aware for each macro
lib/eal/common/eal_common_lcore.c | 279 ++++++++++++++++++++++++++++--
lib/eal/include/rte_lcore.h | 89 ++++++++++
2 files changed, 356 insertions(+), 12 deletions(-)
