Re: [PATCH v2 6/6] bpf: add new test test_many_kprobe

The test compares old text based kprobe API with PERF_TYPE_KPROBE.

Here is a sample output of this test:

Creating 1000 kprobes with text-based API takes 6.979683 seconds
Cleaning 1000 kprobes with text-based API takes 84.897687 seconds
Creating 1000 kprobes with PERF_TYPE_KPROBE (function name) takes 5.077558 seconds
Cleaning 1000 kprobes with PERF_TYPE_KPROBE (function name) takes 81.241354 seconds
Creating 1000 kprobes with PERF_TYPE_KPROBE (function addr) takes 5.218255 seconds
Cleaning 1000 kprobes with PERF_TYPE_KPROBE (function addr) takes 80.010731 seconds

Signed-off-by: Song Liu <redacted>
Reviewed-by: Josef Bacik <redacted>
---
 samples/bpf/Makefile                |   3 +
 samples/bpf/bpf_load.c              |   5 +-
 samples/bpf/bpf_load.h              |   4 +
 samples/bpf/test_many_kprobe_user.c | 182 ++++++++++++++++++++++++++++++++++++
 4 files changed, 191 insertions(+), 3 deletions(-)
 create mode 100644 samples/bpf/test_many_kprobe_user.c

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 9b4a66e..ec92f35 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile

@@ -42,6 +42,7 @@ hostprogs-y += xdp_redirect
 hostprogs-y += xdp_redirect_map
 hostprogs-y += xdp_monitor
 hostprogs-y += syscall_tp
+hostprogs-y += test_many_kprobe

 # Libbpf dependencies
 LIBBPF := ../../tools/lib/bpf/bpf.o

@@ -87,6 +88,7 @@ xdp_redirect-objs := bpf_load.o $(LIBBPF) xdp_redirect_user.o
 xdp_redirect_map-objs := bpf_load.o $(LIBBPF) xdp_redirect_map_user.o
 xdp_monitor-objs := bpf_load.o $(LIBBPF) xdp_monitor_user.o
 syscall_tp-objs := bpf_load.o $(LIBBPF) syscall_tp_user.o
+test_many_kprobe-objs := bpf_load.o $(LIBBPF) test_many_kprobe_user.o

 # Tell kbuild to always build the programs
 always := $(hostprogs-y)

@@ -172,6 +174,7 @@ HOSTLOADLIBES_xdp_redirect += -lelf
 HOSTLOADLIBES_xdp_redirect_map += -lelf
 HOSTLOADLIBES_xdp_monitor += -lelf
 HOSTLOADLIBES_syscall_tp += -lelf
+HOSTLOADLIBES_test_many_kprobe += -lelf

 # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
 #  make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang

diff --git a/samples/bpf/bpf_load.c b/samples/bpf/bpf_load.c
index 872510e..caba9bc 100644
--- a/samples/bpf/bpf_load.c
+++ b/samples/bpf/bpf_load.c

@@ -635,9 +635,8 @@ void read_trace_pipe(void)
        }
 }

-#define MAX_SYMS 300000
-static struct ksym syms[MAX_SYMS];
-static int sym_cnt;
+struct ksym syms[MAX_SYMS];
+int sym_cnt;

 static int ksym_cmp(const void *p1, const void *p2)
 {

diff --git a/samples/bpf/bpf_load.h b/samples/bpf/bpf_load.h
index e7a8a21..16bc263 100644
--- a/samples/bpf/bpf_load.h
+++ b/samples/bpf/bpf_load.h

@@ -67,6 +67,10 @@ static inline __u64 ptr_to_u64(const void *ptr)
        return (__u64) (unsigned long) ptr;
 }

+#define MAX_SYMS 300000
+extern struct ksym syms[MAX_SYMS];
+extern int sym_cnt;
+
 int load_kallsyms(void);
 struct ksym *ksym_search(long key);
 int set_link_xdp_fd(int ifindex, int fd, __u32 flags);

diff --git a/samples/bpf/test_many_kprobe_user.c b/samples/bpf/test_many_kprobe_user.c
new file mode 100644
index 0000000..1f3ee07
--- /dev/null
+++ b/samples/bpf/test_many_kprobe_user.c

@@ -0,0 +1,182 @@
+/* Copyright (c) 2017 Facebook
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */