Current mempool per core cache implementation stores pointers to mbufs On 64b architectures, each pointer consumes 8B This patch replaces it with index-based implementation, where in each buffer is addressed by (pool base address + index) It reduces the amount of memory/cache required for per core cache
L3Fwd performance testing reveals minor improvements in the cache performance (L1 and L2 misses reduced by 0.60%) with no change in throughput Micro-benchmarking the patch using mempool_perf_test shows significant improvement with majority of the test cases Number of cores = 1: n_get_bulk=1 n_put_bulk=1 n_keep=32 %_change_with_patch=18.01 n_get_bulk=1 n_put_bulk=1 n_keep=128 %_change_with_patch=19.91 n_get_bulk=1 n_put_bulk=4 n_keep=32 %_change_with_patch=-20.37 (regression) n_get_bulk=1 n_put_bulk=4 n_keep=128 %_change_with_patch=-17.01 (regression) n_get_bulk=1 n_put_bulk=32 n_keep=32 %_change_with_patch=-25.06 (regression) n_get_bulk=1 n_put_bulk=32 n_keep=128 %_change_with_patch=-23.81 (regression) n_get_bulk=4 n_put_bulk=1 n_keep=32 %_change_with_patch=53.93 n_get_bulk=4 n_put_bulk=1 n_keep=128 %_change_with_patch=60.90 n_get_bulk=4 n_put_bulk=4 n_keep=32 %_change_with_patch=1.64 n_get_bulk=4 n_put_bulk=4 n_keep=128 %_change_with_patch=8.76 n_get_bulk=4 n_put_bulk=32 n_keep=32 %_change_with_patch=-4.71 (regression) n_get_bulk=4 n_put_bulk=32 n_keep=128 %_change_with_patch=-3.19 (regression) n_get_bulk=32 n_put_bulk=1 n_keep=32 %_change_with_patch=65.63 n_get_bulk=32 n_put_bulk=1 n_keep=128 %_change_with_patch=75.19 n_get_bulk=32 n_put_bulk=4 n_keep=32 %_change_with_patch=11.75 n_get_bulk=32 n_put_bulk=4 n_keep=128 %_change_with_patch=15.52 n_get_bulk=32 n_put_bulk=32 n_keep=32 %_change_with_patch=13.45 n_get_bulk=32 n_put_bulk=32 n_keep=128 %_change_with_patch=11.58 Number of core = 2: n_get_bulk=1 n_put_bulk=1 n_keep=32 %_change_with_patch=18.21 n_get_bulk=1 n_put_bulk=1 n_keep=128 %_change_with_patch=21.89 n_get_bulk=1 n_put_bulk=4 n_keep=32 %_change_with_patch=-21.21 (regression) n_get_bulk=1 n_put_bulk=4 n_keep=128 %_change_with_patch=-17.05 (regression) n_get_bulk=1 n_put_bulk=32 n_keep=32 %_change_with_patch=-26.09 (regression) n_get_bulk=1 n_put_bulk=32 n_keep=128 %_change_with_patch=-23.49 (regression) n_get_bulk=4 n_put_bulk=1 n_keep=32 %_change_with_patch=56.28 n_get_bulk=4 n_put_bulk=1 n_keep=128 %_change_with_patch=67.69 n_get_bulk=4 n_put_bulk=4 n_keep=32 %_change_with_patch=1.45 n_get_bulk=4 n_put_bulk=4 n_keep=128 %_change_with_patch=8.84 n_get_bulk=4 n_put_bulk=32 n_keep=32 %_change_with_patch=-5.27 (regression) n_get_bulk=4 n_put_bulk=32 n_keep=128 %_change_with_patch=-3.09 (regression) n_get_bulk=32 n_put_bulk=1 n_keep=32 %_change_with_patch=76.11 n_get_bulk=32 n_put_bulk=1 n_keep=128 %_change_with_patch=86.06 n_get_bulk=32 n_put_bulk=4 n_keep=32 %_change_with_patch=11.86 n_get_bulk=32 n_put_bulk=4 n_keep=128 %_change_with_patch=16.55 n_get_bulk=32 n_put_bulk=32 n_keep=32 %_change_with_patch=13.01 n_get_bulk=32 n_put_bulk=32 n_keep=128 %_change_with_patch=11.51 >From analyzing the results, it is clear that for n_get_bulk and n_put_bulk sizes of 32 there is no performance regression IMO, the other sizes are not practical from performance perspective and the regression in those cases can be safely ignored An attempt to increase the size of mempool to 32GB, by dividing the index by sizeof(uintptr_t), has led to a performance degradation of ~5% compared to the base performance --- v2: - Increase size of mempool to 32GB (Morten) - Improve performance for other platforms using dual loop unrolling --- Dharmik Thakkar (1): mempool: implement index-based per core cache lib/mempool/rte_mempool.h | 150 +++++++++++++++++++++++++- lib/mempool/rte_mempool_ops_default.c | 7 ++ 2 files changed, 156 insertions(+), 1 deletion(-) -- 2.17.1
