On Wed, Jul 05, 2023 at 11:03:25AM +0800, Hou Tao wrote: > Hi, > > On 7/4/2023 11:02 PM, Anton Protopopov wrote: > > On Tue, Jul 04, 2023 at 10:41:10PM +0800, Hou Tao wrote: > >> Hi, > >> > >> On 6/30/2023 4:25 PM, Anton Protopopov wrote: > >>> Add a new map test, map_percpu_stats.c, which is checking the correctness of > >>> map's percpu elements counters. For supported maps the test upserts a number > >>> of elements, checks the correctness of the counters, then deletes all the > >>> elements and checks again that the counters sum drops down to zero. > >>> > >>> The following map types are tested: > >>> > >>> * BPF_MAP_TYPE_HASH, BPF_F_NO_PREALLOC > >>> * BPF_MAP_TYPE_PERCPU_HASH, BPF_F_NO_PREALLOC > >>> * BPF_MAP_TYPE_HASH, > >>> * BPF_MAP_TYPE_PERCPU_HASH, > >>> * BPF_MAP_TYPE_LRU_HASH > >>> * BPF_MAP_TYPE_LRU_PERCPU_HASH > >> A test for BPF_MAP_TYPE_HASH_OF_MAPS is also needed. > We could also exercise the test for LRU map with BPF_F_NO_COMMON_LRU. Thanks, added. > > > SNIP > >>> diff --git a/tools/testing/selftests/bpf/map_tests/map_percpu_stats.c b/tools/testing/selftests/bpf/map_tests/map_percpu_stats.c > >>> new file mode 100644 > >>> index 000000000000..5b45af230368 > >>> --- /dev/null > >>> +++ b/tools/testing/selftests/bpf/map_tests/map_percpu_stats.c > >>> @@ -0,0 +1,336 @@ > >>> +// SPDX-License-Identifier: GPL-2.0 > >>> +/* Copyright (c) 2023 Isovalent */ > >>> + > >>> +#include <errno.h> > >>> +#include <unistd.h> > >>> +#include <pthread.h> > >>> + > >>> +#include <bpf/bpf.h> > >>> +#include <bpf/libbpf.h> > >>> + > >>> +#include <bpf_util.h> > >>> +#include <test_maps.h> > >>> + > >>> +#include "map_percpu_stats.skel.h" > >>> + > >>> +#define MAX_ENTRIES 16384 > >>> +#define N_THREADS 37 > >> Why 37 thread is needed here ? Does a small number of threads work as well ? > > This was used to evict more elements from LRU maps when they are full. > > I see. But in my understanding, for the global LRU list, the eviction > (the invocation of htab_lru_map_delete_node) will be possible if the > free element is less than LOCAL_FREE_TARGET(128) * nr_running_cpus. Now > the number of free elements is 1000 as defined in __test(), the number > of vCPU is 8 in my local VM setup (BPF CI also uses 8 vCPUs) and it is > hard to trigger the eviction because 8 * 128 is roughly equal with 1000. > So I suggest to decrease the number of free elements to 512 and the > number of threads to 8, or adjust the number of running thread and free > elements according to the number of online CPUs. Yes, makes sense. I've changed the test to use 8 threads and offset of 512.
