From 5ed3ccbd5ac11414d61c16182718e68868becc16 Mon Sep 17 00:00:00 2001 From: Kaixu Xia Date: Wed, 12 Aug 2015 09:37:53 +0000 Subject: [PATCH] bpf: fix build warnings and add function read_trace_pipe() There are two improvements in this patch: 1. Fix the build warnings; 2. Add function read_trace_pipe() to print the result on the screen; Before this patch, we can get the result through /sys/kernel/de bug/tracing/trace_pipe and get nothing on the screen. By applying this patch, the result can be printed on the screen. $ ./tracex6 ... tracex6-705 [003] d..1 131.428593: : CPU-3 19981414 sshd-683 [000] d..1 131.428727: : CPU-0 221682321 sshd-683 [000] d..1 131.428821: : CPU-0 221808766 sshd-683 [000] d..1 131.428950: : CPU-0 221982984 sshd-683 [000] d..1 131.429045: : CPU-0 222111851 tracex6-705 [003] d..1 131.429168: : CPU-3 20757551 sshd-683 [000] d..1 131.429170: : CPU-0 222281240 sshd-683 [000] d..1 131.429261: : CPU-0 222403340 sshd-683 [000] d..1 131.429378: : CPU-0 222561024 ... Signed-off-by: Kaixu Xia Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- samples/bpf/tracex6_kern.c | 1 + samples/bpf/tracex6_user.c | 22 +++++++++++++--------- 2 files changed, 14 insertions(+), 9 deletions(-) diff --git a/samples/bpf/tracex6_kern.c b/samples/bpf/tracex6_kern.c index 23d1cffaf249..be479c4af9e2 100644 --- a/samples/bpf/tracex6_kern.c +++ b/samples/bpf/tracex6_kern.c @@ -1,3 +1,4 @@ +#include #include #include #include "bpf_helpers.h" diff --git a/samples/bpf/tracex6_user.c b/samples/bpf/tracex6_user.c index 928f05eaa304..8ea4976cfcf1 100644 --- a/samples/bpf/tracex6_user.c +++ b/samples/bpf/tracex6_user.c @@ -17,8 +17,7 @@ static void test_bpf_perf_event(void) { int nr_cpus = sysconf(_SC_NPROCESSORS_CONF); int *pmu_fd = malloc(nr_cpus * sizeof(int)); - unsigned long value; - int i; + int status, i; struct perf_event_attr attr_insn_pmu = { .freq = 0, @@ -32,22 +31,26 @@ static void test_bpf_perf_event(void) for (i = 0; i < nr_cpus; i++) { pmu_fd[i] = perf_event_open(&attr_insn_pmu, -1/*pid*/, i/*cpu*/, -1/*group_fd*/, 0); - if (pmu_fd[i] < 0) + if (pmu_fd[i] < 0) { printf("event syscall failed\n"); + goto exit; + } bpf_update_elem(map_fd[0], &i, &pmu_fd[i], BPF_ANY); ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0); } - system("ls"); - system("pwd"); - system("sleep 2"); + status = system("ls > /dev/null"); + if (status) + goto exit; + status = system("sleep 2"); + if (status) + goto exit; +exit: for (i = 0; i < nr_cpus; i++) close(pmu_fd[i]); - - close(map_fd); - + close(map_fd[0]); free(pmu_fd); } @@ -63,6 +66,7 @@ int main(int argc, char **argv) } test_bpf_perf_event(); + read_trace_pipe(); return 0; } -- 2.30.2