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Commit 5ed3ccbd authored Aug 12, 2015 by Kaixu Xia Committed by David S. Miller Aug 12, 2015

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 <xiakaixu@huawei.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 47b344b2

samples/bpf/tracex6_kern.c

+1 −0

Original line number	Diff line number	Diff line
		#include <linux/ptrace.h>
		#include <linux/version.h>
		#include <uapi/linux/bpf.h>
		#include "bpf_helpers.h"

samples/bpf/tracex6_user.c

+13 −9

Original line number	Diff line number	Diff line
		@@ -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;
		}