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bpf: fix build warnings and add function read_trace_pipe()

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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>
This commit is contained in:
Kaixu Xia 2015-08-12 09:37:53 +00:00 committed by David S. Miller
parent 47b344b27a
commit 5ed3ccbd5a
2 changed files with 14 additions and 9 deletions
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1
samples/bpf/tracex6_kern.c
View File

@ -1,3 +1,4 @@
#include <linux/ptrace.h>
#include <linux/version.h>
#include <uapi/linux/bpf.h>
#include "bpf_helpers.h"

22
samples/bpf/tracex6_user.c
View File

@ -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;
}