lwn.git/samples/bpf/map_perf_test_kern.c, branch v5.16-rc3

samples: bpf: Refactor BPF map performance test with libbpf

2020-07-07T23:33:14+00:00

Previously, in order to set the numa_node attribute at the time of map creation using "libbpf", it was necessary to call bpf_create_map_node() directly (bpf_load approach), instead of calling bpf_object_load() that handles everything on its own, including map creation. And because of this problem, this sample had problems with refactoring from bpf_load to libbbpf. However, by commit 1bdb6c9a1c43 ("libbpf: Add a bunch of attribute getters/setters for map definitions") added the numa_node attribute and allowed it to be set in the map. By using libbpf instead of bpf_load, the inner map definition has been explicitly declared with BTF-defined format. Also, the element of ARRAY_OF_MAPS was also statically specified using the BTF format. And for this reason some logic in fixup_map() was not needed and changed or removed. Signed-off-by: Daniel T. Lee Signed-off-by: Daniel Borkmann Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200707184855.30968-4-danieltimlee@gmail.com

samples: bpf: Fix bpf programs with kprobe/sys_connect event

2020-07-07T23:32:14+00:00

Currently, BPF programs with kprobe/sys_connect does not work properly. Commit 34745aed515c ("samples/bpf: fix kprobe attachment issue on x64") This commit modifies the bpf_load behavior of kprobe events in the x64 architecture. If the current kprobe event target starts with "sys_*", add the prefix "__x64_" to the front of the event. Appending "__x64_" prefix with kprobe/sys_* event was appropriate as a solution to most of the problems caused by the commit below. commit d5a00528b58c ("syscalls/core, syscalls/x86: Rename struct pt_regs-based sys_*() to __x64_sys_*()") However, there is a problem with the sys_connect kprobe event that does not work properly. For __sys_connect event, parameters can be fetched normally, but for __x64_sys_connect, parameters cannot be fetched. ffffffff818d3520 <__x64_sys_connect>: ffffffff818d3520: e8 fb df 32 00 callq 0xffffffff81c01520 <__fentry__> ffffffff818d3525: 48 8b 57 60 movq 96(%rdi), %rdx ffffffff818d3529: 48 8b 77 68 movq 104(%rdi), %rsi ffffffff818d352d: 48 8b 7f 70 movq 112(%rdi), %rdi ffffffff818d3531: e8 1a ff ff ff callq 0xffffffff818d3450 <__sys_connect> ffffffff818d3536: 48 98 cltq ffffffff818d3538: c3 retq ffffffff818d3539: 0f 1f 80 00 00 00 00 nopl (%rax) As the assembly code for __x64_sys_connect shows, parameters should be fetched and set into rdi, rsi, rdx registers prior to calling __sys_connect. Because of this problem, this commit fixes the sys_connect event by first getting the value of the rdi register and then the value of the rdi, rsi, and rdx register through an offset based on that value. Fixes: 34745aed515c ("samples/bpf: fix kprobe attachment issue on x64") Signed-off-by: Daniel T. Lee Signed-off-by: Daniel Borkmann Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200707184855.30968-2-danieltimlee@gmail.com

samples/bpf: Use consistent include paths for libbpf

2020-01-21T00:37:45+00:00

Fix all files in samples/bpf to include libbpf header files with the bpf/ prefix, to be consistent with external users of the library. Also ensure that all includes of exported libbpf header files (those that are exported on 'make install' of the library) use bracketed includes instead of quoted. To make sure no new files are introduced that doesn't include the bpf/ prefix in its include, remove tools/lib/bpf from the include path entirely, and use tools/lib instead. Fixes: 6910d7d3867a ("selftests/bpf: Ensure bpf_helper_defs.h are taken from selftests dir") Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Alexei Starovoitov Acked-by: Jesper Dangaard Brouer Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/157952560911.1683545.8795966751309534150.stgit@toke.dk

bpf, samples: Use bpf_probe_read_user where appropriate

2019-11-02T19:39:13+00:00

Use bpf_probe_read_user() helper instead of bpf_probe_read() for samples that attach to kprobes probing on user addresses. Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/5b0144b3f8e031ec5e2438bd7de8d7877e63bf2f.1572649915.git.daniel@iogearbox.net

selftests/bpf: Split off tracing-only helpers into bpf_tracing.h

2019-10-08T21:16:03+00:00

Split-off PT_REGS-related helpers into bpf_tracing.h header. Adjust selftests and samples to include it where necessary. Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20191008175942.1769476-5-andriin@fb.com

selftests/bpf: samples/bpf: Split off legacy stuff from bpf_helpers.h

2019-10-08T21:16:03+00:00

Split off few legacy things from bpf_helpers.h into separate bpf_legacy.h file: - load_{byte|half|word}; - remove extra inner_idx and numa_node fields from bpf_map_def and introduce bpf_map_def_legacy for use in samples; - move BPF_ANNOTATE_KV_PAIR into bpf_legacy.h. Adjust samples and selftests accordingly by either including bpf_legacy.h and using bpf_map_def_legacy, or switching to BTF-defined maps altogether. Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20191008175942.1769476-3-andriin@fb.com

samples/bpf: Use getppid instead of getpgrp for array map stress

2017-09-21T18:59:16+00:00

When cross-compiling the bpf sample map_perf_test for aarch64, I find that __NR_getpgrp is undefined. This causes build errors. This syscall is deprecated and requires defining __ARCH_WANT_SYSCALL_DEPRECATED. To avoid having to define that, just use a different syscall (getppid) for the array map stress test. Acked-by: Alexei Starovoitov Signed-off-by: Joel Fernandes Acked-by: Daniel Borkmann Signed-off-by: David S. Miller

bpf: Add lru_hash_lookup performance test

2017-09-01T16:57:38+00:00

Create a new case to test the LRU lookup performance. At the beginning, the LRU map is fully loaded (i.e. the number of keys is equal to map->max_entries). The lookup is done through key 0 to num_map_entries and then repeats from 0 again. This patch also creates an anonymous struct to properly name the test params in stress_lru_hmap_alloc() in map_perf_test_kern.c. Signed-off-by: Martin KaFai Lau Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller

bpf: Allow numa selection in INNER_LRU_HASH_PREALLOC test of map_perf_test

2017-08-20T04:35:43+00:00

This patch makes the needed changes to allow each process of the INNER_LRU_HASH_PREALLOC test to provide its numa node id when creating the lru map. Signed-off-by: Martin KaFai Lau Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller

bpf: lru: Add map-in-map LRU example

2017-04-17T17:55:52+00:00

This patch adds a map-in-map LRU example. If we know only a subset of cores will use the LRU, we can allocate a common LRU list per targeting core and store it into an array-of-hashs. It allows using the common LRU map with map-update performance comparable to the BPF_F_NO_COMMON_LRU map but without wasting memory on the unused cores that we know they will never access the LRU map. BPF_F_NO_COMMON_LRU: > map_perf_test 32 8 10000000 10000000 | awk '{sum += $3}END{print sum}' 9234314 (9.23M/s) map-in-map LRU: > map_perf_test 512 8 1260000 80000000 | awk '{sum += $3}END{print sum}' 9962743 (9.96M/s) Notes that the max_entries for the map-in-map LRU test is 1260000 which is the max_entries for each inner LRU map. 8 processes have been started, so 8 * 1260000 = 10080000 (~10M) which is close to what is used in the BPF_F_NO_COMMON_LRU test. Signed-off-by: Martin KaFai Lau Signed-off-by: David S. Miller