91 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			91 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2021 Facebook */
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#define _GNU_SOURCE
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#include <pthread.h>
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#include <sched.h>
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#include <test_progs.h>
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#include "test_perf_link.skel.h"
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static void burn_cpu(void)
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{
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	volatile int j = 0;
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	cpu_set_t cpu_set;
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	int i, err;
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	/* generate some branches on cpu 0 */
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	CPU_ZERO(&cpu_set);
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	CPU_SET(0, &cpu_set);
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	err = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set), &cpu_set);
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	ASSERT_OK(err, "set_thread_affinity");
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	/* spin the loop for a while (random high number) */
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	for (i = 0; i < 1000000; ++i)
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		++j;
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}
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/* TODO: often fails in concurrent mode */
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void serial_test_perf_link(void)
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{
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	struct test_perf_link *skel = NULL;
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	struct perf_event_attr attr;
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	int pfd = -1, link_fd = -1, err;
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	int run_cnt_before, run_cnt_after;
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	struct bpf_link_info info;
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	__u32 info_len = sizeof(info);
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	/* create perf event */
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	memset(&attr, 0, sizeof(attr));
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	attr.size = sizeof(attr);
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	attr.type = PERF_TYPE_SOFTWARE;
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	attr.config = PERF_COUNT_SW_CPU_CLOCK;
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	attr.freq = 1;
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	attr.sample_freq = 1000;
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	pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC);
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	if (!ASSERT_GE(pfd, 0, "perf_fd"))
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		goto cleanup;
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	skel = test_perf_link__open_and_load();
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	if (!ASSERT_OK_PTR(skel, "skel_load"))
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		goto cleanup;
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	link_fd = bpf_link_create(bpf_program__fd(skel->progs.handler), pfd,
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				  BPF_PERF_EVENT, NULL);
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	if (!ASSERT_GE(link_fd, 0, "link_fd"))
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		goto cleanup;
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	memset(&info, 0, sizeof(info));
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	err = bpf_obj_get_info_by_fd(link_fd, &info, &info_len);
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	if (!ASSERT_OK(err, "link_get_info"))
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		goto cleanup;
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	ASSERT_EQ(info.type, BPF_LINK_TYPE_PERF_EVENT, "link_type");
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	ASSERT_GT(info.id, 0, "link_id");
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	ASSERT_GT(info.prog_id, 0, "link_prog_id");
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	/* ensure we get at least one perf_event prog execution */
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	burn_cpu();
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	ASSERT_GT(skel->bss->run_cnt, 0, "run_cnt");
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	/* perf_event is still active, but we close link and BPF program
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	 * shouldn't be executed anymore
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	 */
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	close(link_fd);
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	link_fd = -1;
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	/* make sure there are no stragglers */
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	kern_sync_rcu();
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	run_cnt_before = skel->bss->run_cnt;
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	burn_cpu();
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	run_cnt_after = skel->bss->run_cnt;
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	ASSERT_EQ(run_cnt_before, run_cnt_after, "run_cnt_before_after");
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cleanup:
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	if (link_fd >= 0)
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		close(link_fd);
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	if (pfd >= 0)
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		close(pfd);
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	test_perf_link__destroy(skel);
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}
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