mirror of https://gitee.com/openkylin/linux.git
492e0d0d6f
Grabbing the spinlock for every bucket even if it's empty, was causing
significant perfomance cost when traversing htab maps that have only a
few entries. This patch addresses the issue by checking first the
bucket_cnt, if the bucket has some entries then we go and grab the
spinlock and proceed with the batching.
Tested with a htab of size 50K and different value of populated entries.
Before:
Benchmark Time(ns) CPU(ns)
---------------------------------------------
BM_DumpHashMap/1 2759655 2752033
BM_DumpHashMap/10 2933722 2930825
BM_DumpHashMap/200 3171680 3170265
BM_DumpHashMap/500 3639607 3635511
BM_DumpHashMap/1000 4369008 4364981
BM_DumpHashMap/5k 11171919 11134028
BM_DumpHashMap/20k 69150080 69033496
BM_DumpHashMap/39k 190501036 190226162
After:
Benchmark Time(ns) CPU(ns)
---------------------------------------------
BM_DumpHashMap/1 202707 200109
BM_DumpHashMap/10 213441 210569
BM_DumpHashMap/200 478641 472350
BM_DumpHashMap/500 980061 967102
BM_DumpHashMap/1000 1863835 1839575
BM_DumpHashMap/5k 8961836 8902540
BM_DumpHashMap/20k 69761497 69322756
BM_DumpHashMap/39k 187437830 186551111
Fixes:
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||
|---|---|---|
| .. | ||
| Makefile | ||
| arraymap.c | ||
| bpf_lru_list.c | ||
| bpf_lru_list.h | ||
| bpf_struct_ops.c | ||
| bpf_struct_ops_types.h | ||
| btf.c | ||
| cgroup.c | ||
| core.c | ||
| cpumap.c | ||
| devmap.c | ||
| disasm.c | ||
| disasm.h | ||
| dispatcher.c | ||
| hashtab.c | ||
| helpers.c | ||
| inode.c | ||
| local_storage.c | ||
| lpm_trie.c | ||
| map_in_map.c | ||
| map_in_map.h | ||
| offload.c | ||
| percpu_freelist.c | ||
| percpu_freelist.h | ||
| queue_stack_maps.c | ||
| reuseport_array.c | ||
| stackmap.c | ||
| syscall.c | ||
| sysfs_btf.c | ||
| tnum.c | ||
| trampoline.c | ||
| verifier.c | ||
| xskmap.c | ||