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Commit 12fe1225 authored by Teng Qin's avatar Teng Qin Committed by Daniel Borkmann
Browse files

samples/bpf: add example to test reading address 



This commit adds additional test in the trace_event example, by
attaching the bpf program to MEM_UOPS_RETIRED.LOCK_LOADS event with
PERF_SAMPLE_ADDR requested, and print the lock address value read from
the bpf program to trace_pipe.

Signed-off-by: default avatarTeng Qin <qinteng@fb.com>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
parent 95da0cdb

samples/bpf/trace_event_kern.c

+4 −0
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ int bpf_prog1(struct bpf_perf_event_data *ctx) 
{

	char time_fmt1[] = "Time Enabled: %llu, Time Running: %llu";

	char time_fmt2[] = "Get Time Failed, ErrCode: %d";

	char addr_fmt[] = "Address recorded on event: %llx";

	char fmt[] = "CPU-%d period %lld ip %llx";

	u32 cpu = bpf_get_smp_processor_id();

	struct bpf_perf_event_value value_buf;
@@ -64,6 +65,9 @@ int bpf_prog1(struct bpf_perf_event_data *ctx) 
	else

	  bpf_trace_printk(time_fmt2, sizeof(time_fmt2), ret);



	if (ctx->addr != 0)

	  bpf_trace_printk(addr_fmt, sizeof(addr_fmt), ctx->addr);



	val = bpf_map_lookup_elem(&counts, &key);

	if (val)

		(*val)++;

samples/bpf/trace_event_user.c

+15 −0
Original line number Diff line number Diff line
@@ -215,6 +215,17 @@ static void test_bpf_perf_event(void) 
		/* Intel Instruction Retired */

		.config = 0xc0,

	};

	struct perf_event_attr attr_type_raw_lock_load = {

		.sample_freq = SAMPLE_FREQ,

		.freq = 1,

		.type = PERF_TYPE_RAW,

		/* Intel MEM_UOPS_RETIRED.LOCK_LOADS */

		.config = 0x21d0,

		/* Request to record lock address from PEBS */

		.sample_type = PERF_SAMPLE_ADDR,

		/* Record address value requires precise event */

		.precise_ip = 2,

	};



	printf("Test HW_CPU_CYCLES\n");

	test_perf_event_all_cpu(&attr_type_hw);
@@ -236,6 +247,10 @@ static void test_bpf_perf_event(void) 
	test_perf_event_all_cpu(&attr_type_raw);

	test_perf_event_task(&attr_type_raw);



	printf("Test Lock Load\n");

	test_perf_event_all_cpu(&attr_type_raw_lock_load);

	test_perf_event_task(&attr_type_raw_lock_load);



	printf("*** PASS ***\n");

}