From 22adedd304668f0a2001284ddf225b49e9c05c64 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Date: Mon, 25 Jun 2018 14:25:02 +0200 Subject: [PATCH] trace_helpers.c: Add helpers to poll multiple perf FDs for events MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Add two new helper functions to trace_helpers that supports polling multiple perf file descriptors for events. These are used to the XDP perf_event_output example, which needs to work with one perf fd per CPU. Reviewed-by: Jakub Kicinski Signed-off-by: Toke Høiland-Jørgensen Acked-by: Song Liu Signed-off-by: Daniel Borkmann --- tools/testing/selftests/bpf/trace_helpers.c | 48 ++++++++++++++++++++- tools/testing/selftests/bpf/trace_helpers.h | 4 ++ 2 files changed, 50 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/trace_helpers.c b/tools/testing/selftests/bpf/trace_helpers.c index 3868dcb63420..cabe2a3a3b30 100644 --- a/tools/testing/selftests/bpf/trace_helpers.c +++ b/tools/testing/selftests/bpf/trace_helpers.c @@ -88,7 +88,7 @@ static int page_size; static int page_cnt = 8; static struct perf_event_mmap_page *header; -int perf_event_mmap(int fd) +int perf_event_mmap_header(int fd, struct perf_event_mmap_page **header) { void *base; int mmap_size; @@ -102,10 +102,15 @@ int perf_event_mmap(int fd) return -1; } - header = base; + *header = base; return 0; } +int perf_event_mmap(int fd) +{ + return perf_event_mmap_header(fd, &header); +} + static int perf_event_poll(int fd) { struct pollfd pfd = { .fd = fd, .events = POLLIN }; @@ -163,3 +168,42 @@ int perf_event_poller(int fd, perf_event_print_fn output_fn) return ret; } + +int perf_event_poller_multi(int *fds, struct perf_event_mmap_page **headers, + int num_fds, perf_event_print_fn output_fn) +{ + enum bpf_perf_event_ret ret; + struct pollfd *pfds; + void *buf = NULL; + size_t len = 0; + int i; + + pfds = calloc(num_fds, sizeof(*pfds)); + if (!pfds) + return LIBBPF_PERF_EVENT_ERROR; + + for (i = 0; i < num_fds; i++) { + pfds[i].fd = fds[i]; + pfds[i].events = POLLIN; + } + + for (;;) { + poll(pfds, num_fds, 1000); + for (i = 0; i < num_fds; i++) { + if (!pfds[i].revents) + continue; + + ret = bpf_perf_event_read_simple(headers[i], + page_cnt * page_size, + page_size, &buf, &len, + bpf_perf_event_print, + output_fn); + if (ret != LIBBPF_PERF_EVENT_CONT) + break; + } + } + free(buf); + free(pfds); + + return ret; +} diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h index 3b4bcf7f5084..18924f23db1b 100644 --- a/tools/testing/selftests/bpf/trace_helpers.h +++ b/tools/testing/selftests/bpf/trace_helpers.h @@ -3,6 +3,7 @@ #define __TRACE_HELPER_H #include +#include struct ksym { long addr; @@ -16,6 +17,9 @@ long ksym_get_addr(const char *name); typedef enum bpf_perf_event_ret (*perf_event_print_fn)(void *data, int size); int perf_event_mmap(int fd); +int perf_event_mmap_header(int fd, struct perf_event_mmap_page **header); /* return LIBBPF_PERF_EVENT_DONE or LIBBPF_PERF_EVENT_ERROR */ int perf_event_poller(int fd, perf_event_print_fn output_fn); +int perf_event_poller_multi(int *fds, struct perf_event_mmap_page **headers, + int num_fds, perf_event_print_fn output_fn); #endif -- 2.39.5