libbpf-tools: add profile

Signed-off-by: Eunseon Lee <[email protected]>

libbpf-tools/Makefile

@@ -54,6 +54,7 @@ APPS = \
 	tcpconnlat \
 	tcprtt \
 	vfsstat \
+	profile \
 	#
 
 FSDIST_ALIASES = btrfsdist ext4dist nfsdist xfsdist

libbpf-tools/profile.bpf.c

@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2021 Wenbo Zhang
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_tracing.h>
+#include "profile.h"
+
+#define PF_KTHREAD		0x00200000	/* I am a kernel thread */
+#define MAX_ENTRIES		10240
+
+const volatile bool kernel_stacks_only = false;
+const volatile bool user_stacks_only = false;
+const volatile bool include_idle = false;
+const volatile pid_t targ_tgid = -1;
+const volatile pid_t targ_pid = -1;
+
+struct {
+	__uint(type, BPF_MAP_TYPE_STACK_TRACE);
+	__uint(key_size, sizeof(u32));
+} stackmap SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__type(key, struct key_t);
+	__type(value, sizeof(u64));
+	__uint(max_entries, MAX_ENTRIES);
+} counts SEC(".maps");
+
+SEC("perf_event")
+int do_perf_event(struct bpf_perf_event_data *ctx) {
+	u64 id = bpf_get_current_pid_tgid();
+	u32 tgid = id >> 32;
+	u32 pid = id;
+	u32 *valp, val;
+
+	if (include_idle == false && pid == 0)
+		return 0;
+
+	if (targ_tgid != -1 && targ_tgid != tgid)
+		return 0;
+	if (targ_pid != -1 && targ_pid != pid)
+		return 0;
+
+	if (container_should_be_filtered()) {
+			return 0;
+	}
+
+	// create map key
+	struct key_t key = {.pid = tgid};
+	bpf_get_current_comm(&key.name, sizeof(key.name));
+
+	if (user_stacks_only)
+		key.kern_stack_id = -1;
+	else
+		key.kern_stack_id = bpf_get_stackid(ctx, &stackmap, 0);
+
+	if (kernel_stacks_only)
+		key.user_stack_id = -1;
+	else
+		key.user_stack_id = bpf_get_stackid(ctx, &stackmap, BPF_F_USER_STACK);
+
+	if (key.kern_stack_id >= 0) {
+		// populate extras to fix the kernel stack
+		u64 ip = PT_REGS_IP(&ctx->regs);
+		u64 page_offset;
+
+		// if ip isn't sane, leave key ips as zero for later checking
+#if defined(CONFIG_X86_64) && defined(__PAGE_OFFSET_BASE)
+		// x64, 4.16, ..., 4.11, etc., but some earlier kernel didn't have it
+		page_offset = __PAGE_OFFSET_BASE;
+#elif defined(CONFIG_X86_64) && defined(__PAGE_OFFSET_BASE_L4)
+		// x64, 4.17, and later
+#if defined(CONFIG_DYNAMIC_MEMORY_LAYOUT) && defined(CONFIG_X86_5LEVEL)
+		page_offset = __PAGE_OFFSET_BASE_L5;
+#else
+		page_offset = __PAGE_OFFSET_BASE_L4;
+#endif
+#else
+		// earlier x86_64 kernels, e.g., 4.6, comes here
+		// arm64, s390, powerpc, x86_32
+
+		page_offset = PAGE_OFFSET;
+#endif
+
+		if (ip > page_offset) {
+			key.kernel_ip = ip;
+		}
+	}
+
+	valp = bpf_map_lookup_elem(&counts, &key);
+	val = 1;
+	if (!valp)
+		bpf_map_update_elem(&counts, &key, &val, BPF_OK);
+	else
+		__sync_fetch_and_add(&valp, &val);
+	return 0;
+}
+
+char LICENSE[] SEC("license") = "GPL";