From 47efb30274cbec1bd3c0c980a7ece328df2c16a8 Mon Sep 17 00:00:00 2001 From: Kaixu Xia Date: Thu, 6 Aug 2015 07:02:36 +0000 Subject: samples/bpf: example of get selected PMU counter value This is a simple example and shows how to use the new ability to get the selected Hardware PMU counter value. Signed-off-by: Kaixu Xia Signed-off-by: David S. Miller --- samples/bpf/Makefile | 4 +++ samples/bpf/bpf_helpers.h | 2 ++ samples/bpf/tracex6_kern.c | 26 ++++++++++++++++++ samples/bpf/tracex6_user.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 100 insertions(+) create mode 100644 samples/bpf/tracex6_kern.c create mode 100644 samples/bpf/tracex6_user.c (limited to 'samples/bpf') diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 4450fed..63e7d50 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -12,6 +12,7 @@ hostprogs-y += tracex2 hostprogs-y += tracex3 hostprogs-y += tracex4 hostprogs-y += tracex5 +hostprogs-y += tracex6 hostprogs-y += lathist test_verifier-objs := test_verifier.o libbpf.o @@ -25,6 +26,7 @@ tracex2-objs := bpf_load.o libbpf.o tracex2_user.o tracex3-objs := bpf_load.o libbpf.o tracex3_user.o tracex4-objs := bpf_load.o libbpf.o tracex4_user.o tracex5-objs := bpf_load.o libbpf.o tracex5_user.o +tracex6-objs := bpf_load.o libbpf.o tracex6_user.o lathist-objs := bpf_load.o libbpf.o lathist_user.o # Tell kbuild to always build the programs @@ -37,6 +39,7 @@ always += tracex2_kern.o always += tracex3_kern.o always += tracex4_kern.o always += tracex5_kern.o +always += tracex6_kern.o always += tcbpf1_kern.o always += lathist_kern.o @@ -51,6 +54,7 @@ HOSTLOADLIBES_tracex2 += -lelf HOSTLOADLIBES_tracex3 += -lelf HOSTLOADLIBES_tracex4 += -lelf -lrt HOSTLOADLIBES_tracex5 += -lelf +HOSTLOADLIBES_tracex6 += -lelf HOSTLOADLIBES_lathist += -lelf # point this to your LLVM backend with bpf support diff --git a/samples/bpf/bpf_helpers.h b/samples/bpf/bpf_helpers.h index c77c872..3a44d3a 100644 --- a/samples/bpf/bpf_helpers.h +++ b/samples/bpf/bpf_helpers.h @@ -31,6 +31,8 @@ static unsigned long long (*bpf_get_current_uid_gid)(void) = (void *) BPF_FUNC_get_current_uid_gid; static int (*bpf_get_current_comm)(void *buf, int buf_size) = (void *) BPF_FUNC_get_current_comm; +static int (*bpf_perf_event_read)(void *map, int index) = + (void *) BPF_FUNC_perf_event_read; /* llvm builtin functions that eBPF C program may use to * emit BPF_LD_ABS and BPF_LD_IND instructions diff --git a/samples/bpf/tracex6_kern.c b/samples/bpf/tracex6_kern.c new file mode 100644 index 0000000..23d1cff --- /dev/null +++ b/samples/bpf/tracex6_kern.c @@ -0,0 +1,26 @@ +#include +#include +#include "bpf_helpers.h" + +struct bpf_map_def SEC("maps") my_map = { + .type = BPF_MAP_TYPE_PERF_EVENT_ARRAY, + .key_size = sizeof(int), + .value_size = sizeof(u32), + .max_entries = 32, +}; + +SEC("kprobe/sys_write") +int bpf_prog1(struct pt_regs *ctx) +{ + u64 count; + u32 key = bpf_get_smp_processor_id(); + char fmt[] = "CPU-%d %llu\n"; + + count = bpf_perf_event_read(&my_map, key); + bpf_trace_printk(fmt, sizeof(fmt), key, count); + + return 0; +} + +char _license[] SEC("license") = "GPL"; +u32 _version SEC("version") = LINUX_VERSION_CODE; diff --git a/samples/bpf/tracex6_user.c b/samples/bpf/tracex6_user.c new file mode 100644 index 0000000..928f05e --- /dev/null +++ b/samples/bpf/tracex6_user.c @@ -0,0 +1,68 @@ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "libbpf.h" +#include "bpf_load.h" + +#define SAMPLE_PERIOD 0x7fffffffffffffffULL + +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; + + struct perf_event_attr attr_insn_pmu = { + .freq = 0, + .sample_period = SAMPLE_PERIOD, + .inherit = 0, + .type = PERF_TYPE_HARDWARE, + .read_format = 0, + .sample_type = 0, + .config = 0,/* PMU: cycles */ + }; + + 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) + printf("event syscall failed\n"); + + 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"); + + for (i = 0; i < nr_cpus; i++) + close(pmu_fd[i]); + + close(map_fd); + + free(pmu_fd); +} + +int main(int argc, char **argv) +{ + char filename[256]; + + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + + if (load_bpf_file(filename)) { + printf("%s", bpf_log_buf); + return 1; + } + + test_bpf_perf_event(); + + return 0; +} -- cgit v1.1