perf test: Enhance the LLVM test: update basic BPF test program

This patch replaces the original toy BPF program with the previously
introduced bpf-script-example.c. Dynamically embeddeding it into
'llvm-src-base.c'.

The newly introduced BPF program attaches a BPF program to
'sys_epoll_pwait()'. perf itself never use that syscall, so further test
can verify their result with it. The program would generate 1 sample in
every 2 calls of epoll_pwait() system call.

Since the resulting BPF object is useful per se for further tests,
test_llvm__fetch_bpf_obj() is introduced for creating BPF objects from
source. The LLVM test was rewritten to use it.

Committer note:

Running it:

  [root@zoo wb]# perf test -v LLVM
  35: Test LLVM searching and compiling                        :
  --- start ---
  test child forked, pid 17740
  Kernel build dir is set to /lib/modules/4.3.0-rc1+/build
  set env: KBUILD_DIR=/lib/modules/4.3.0-rc1+/build
  unset env: KBUILD_OPTS
  include option is set to  -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/4.9.2/include -I/home/git/linux/arch/x86/include -Iarch/x86/include/generated/uapi -Iarch/x86/include/generated  -I/home/git/linux/include -Iinclude -I/home/git/linux/arch/x86/include/uapi -Iarch/x86/include/generated/uapi -I/home/git/linux/include/uapi -Iinclude/generated/uapi -include /home/git/linux/include/linux/kconfig.h
  set env: NR_CPUS=4
  set env: LINUX_VERSION_CODE=0x40300
  set env: CLANG_EXEC=/usr/libexec/icecc/bin/clang
  set env: CLANG_OPTIONS=-xc
  set env: KERNEL_INC_OPTIONS= -nostdinc -isystem /usr/lib/gcc/x86_64-redhat-linux/4.9.2/include -I/home/git/linux/arch/x86/include -Iarch/x86/include/generated/uapi -Iarch/x86/include/generated  -I/home/git/linux/include -Iinclude -I/home/git/linux/arch/x86/include/uapi -Iarch/x86/include/generated/uapi -I/home/git/linux/include/uapi -Iinclude/generated/uapi -include /home/git/linux/include/linux/kconfig.h
  set env: WORKING_DIR=/lib/modules/4.3.0-rc1+/build
  set env: CLANG_SOURCE=-
  llvm compiling command template: echo '/*
   * bpf-script-example.c
   * Test basic LLVM building
   */
  #ifndef LINUX_VERSION_CODE
  # error Need LINUX_VERSION_CODE
  # error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'
  #endif
  #define BPF_ANY 0
  #define BPF_MAP_TYPE_ARRAY 2
  #define BPF_FUNC_map_lookup_elem 1
  #define BPF_FUNC_map_update_elem 2

  static void *(*bpf_map_lookup_elem)(void *map, void *key) =
	  (void *) BPF_FUNC_map_lookup_elem;
  static void *(*bpf_map_update_elem)(void *map, void *key, void *value, int flags) =
	  (void *) BPF_FUNC_map_update_elem;

  struct bpf_map_def {
	  unsigned int type;
	  unsigned int key_size;
	  unsigned int value_size;
	  unsigned int max_entries;
  };

  #define SEC(NAME) __attribute__((section(NAME), used))
  struct bpf_map_def SEC("maps") flip_table = {
	  .type = BPF_MAP_TYPE_ARRAY,
	  .key_size = sizeof(int),
	  .value_size = sizeof(int),
	  .max_entries = 1,
  };

  SEC("func=sys_epoll_pwait")
  int bpf_func__sys_epoll_pwait(void *ctx)
  {
	  int ind =0;
	  int *flag = bpf_map_lookup_elem(&flip_table, &ind);
	  int new_flag;
	  if (!flag)
		  return 0;
	  /* flip flag and store back */
	  new_flag = !*flag;
	  bpf_map_update_elem(&flip_table, &ind, &new_flag, BPF_ANY);
	  return new_flag;
  }
  char _license[] SEC("license") = "GPL";
  int _version SEC("version") = LINUX_VERSION_CODE;
  ' | $CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS -DLINUX_VERSION_CODE=$LINUX_VERSION_CODE $CLANG_OPTIONS $KERNEL_INC_OPTIONS -Wno-unused-value -Wno-pointer-sign -working-directory $WORKING_DIR -c "$CLANG_SOURCE" -target bpf -O2 -o -
  test child finished with 0
  ---- end ----
  Test LLVM searching and compiling: Ok
  [root@zoo wb]#

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1446817783-86722-6-git-send-email-wangnan0@huawei.com
Signed-off-by: He Kuang <hekuang@huawei.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Wang Nan 2015-11-06 13:49:41 +00:00 committed by Arnaldo Carvalho de Melo
parent d3e0ce3930
commit b31de018a6
4 changed files with 129 additions and 31 deletions

View File

@ -31,9 +31,16 @@ perf-y += sample-parsing.o
perf-y += parse-no-sample-id-all.o
perf-y += kmod-path.o
perf-y += thread-map.o
perf-y += llvm.o
perf-y += llvm.o llvm-src-base.o
perf-y += topology.o
$(OUTPUT)tests/llvm-src-base.c: tests/bpf-script-example.c
$(call rule_mkdir)
$(Q)echo '#include <tests/llvm.h>' > $@
$(Q)echo 'const char test_llvm__bpf_base_prog[] =' >> $@
$(Q)sed -e 's/"/\\"/g' -e 's/\(.*\)/"\1\\n"/g' $< >> $@
$(Q)echo ';' >> $@
ifeq ($(ARCH),$(filter $(ARCH),x86 arm arm64))
perf-$(CONFIG_DWARF_UNWIND) += dwarf-unwind.o
endif

View File

@ -1,3 +1,7 @@
/*
* bpf-script-example.c
* Test basic LLVM building
*/
#ifndef LINUX_VERSION_CODE
# error Need LINUX_VERSION_CODE
# error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200" into llvm section of ~/.perfconfig'

View File

@ -2,6 +2,7 @@
#include <bpf/libbpf.h>
#include <util/llvm-utils.h>
#include <util/cache.h>
#include "llvm.h"
#include "tests.h"
#include "debug.h"
@ -11,16 +12,6 @@ static int perf_config_cb(const char *var, const char *val,
return perf_default_config(var, val, arg);
}
/*
* Randomly give it a "version" section since we don't really load it
* into kernel
*/
static const char test_bpf_prog[] =
"__attribute__((section(\"do_fork\"), used)) "
"int fork(void *ctx) {return 0;} "
"char _license[] __attribute__((section(\"license\"), used)) = \"GPL\";"
"int _version __attribute__((section(\"version\"), used)) = 0x40100;";
#ifdef HAVE_LIBBPF_SUPPORT
static int test__bpf_parsing(void *obj_buf, size_t obj_buf_sz)
{
@ -28,25 +19,47 @@ static int test__bpf_parsing(void *obj_buf, size_t obj_buf_sz)
obj = bpf_object__open_buffer(obj_buf, obj_buf_sz, NULL);
if (IS_ERR(obj))
return -1;
return TEST_FAIL;
bpf_object__close(obj);
return 0;
return TEST_OK;
}
#else
static int test__bpf_parsing(void *obj_buf __maybe_unused,
size_t obj_buf_sz __maybe_unused)
{
pr_debug("Skip bpf parsing\n");
return 0;
return TEST_OK;
}
#endif
int test__llvm(void)
static struct {
const char *source;
const char *desc;
} bpf_source_table[__LLVM_TESTCASE_MAX] = {
[LLVM_TESTCASE_BASE] = {
.source = test_llvm__bpf_base_prog,
.desc = "Basic BPF llvm compiling test",
},
};
int
test_llvm__fetch_bpf_obj(void **p_obj_buf,
size_t *p_obj_buf_sz,
enum test_llvm__testcase index,
bool force)
{
char *tmpl_new, *clang_opt_new;
void *obj_buf;
size_t obj_buf_sz;
int err, old_verbose;
const char *source;
const char *desc;
const char *tmpl_old, *clang_opt_old;
char *tmpl_new = NULL, *clang_opt_new = NULL;
int err, old_verbose, ret = TEST_FAIL;
if (index >= __LLVM_TESTCASE_MAX)
return TEST_FAIL;
source = bpf_source_table[index].source;
desc = bpf_source_table[index].desc;
perf_config(perf_config_cb, NULL);
@ -54,42 +67,100 @@ int test__llvm(void)
* Skip this test if user's .perfconfig doesn't set [llvm] section
* and clang is not found in $PATH, and this is not perf test -v
*/
if (verbose == 0 && !llvm_param.user_set_param && llvm__search_clang()) {
if (!force && (verbose == 0 &&
!llvm_param.user_set_param &&
llvm__search_clang())) {
pr_debug("No clang and no verbosive, skip this test\n");
return TEST_SKIP;
}
old_verbose = verbose;
/*
* llvm is verbosity when error. Suppress all error output if
* not 'perf test -v'.
*/
old_verbose = verbose;
if (verbose == 0)
verbose = -1;
*p_obj_buf = NULL;
*p_obj_buf_sz = 0;
if (!llvm_param.clang_bpf_cmd_template)
return -1;
goto out;
if (!llvm_param.clang_opt)
llvm_param.clang_opt = strdup("");
err = asprintf(&tmpl_new, "echo '%s' | %s", test_bpf_prog,
llvm_param.clang_bpf_cmd_template);
err = asprintf(&tmpl_new, "echo '%s' | %s%s", source,
llvm_param.clang_bpf_cmd_template,
old_verbose ? "" : " 2>/dev/null");
if (err < 0)
return -1;
goto out;
err = asprintf(&clang_opt_new, "-xc %s", llvm_param.clang_opt);
if (err < 0)
return -1;
goto out;
tmpl_old = llvm_param.clang_bpf_cmd_template;
llvm_param.clang_bpf_cmd_template = tmpl_new;
clang_opt_old = llvm_param.clang_opt;
llvm_param.clang_opt = clang_opt_new;
err = llvm__compile_bpf("-", &obj_buf, &obj_buf_sz);
err = llvm__compile_bpf("-", p_obj_buf, p_obj_buf_sz);
llvm_param.clang_bpf_cmd_template = tmpl_old;
llvm_param.clang_opt = clang_opt_old;
verbose = old_verbose;
if (err)
return TEST_FAIL;
goto out;
err = test__bpf_parsing(obj_buf, obj_buf_sz);
free(obj_buf);
return err;
ret = TEST_OK;
out:
free(tmpl_new);
free(clang_opt_new);
if (ret != TEST_OK)
pr_debug("Failed to compile test case: '%s'\n", desc);
return ret;
}
int test__llvm(void)
{
enum test_llvm__testcase i;
for (i = 0; i < __LLVM_TESTCASE_MAX; i++) {
int ret;
void *obj_buf = NULL;
size_t obj_buf_sz = 0;
ret = test_llvm__fetch_bpf_obj(&obj_buf, &obj_buf_sz,
i, false);
if (ret == TEST_OK) {
ret = test__bpf_parsing(obj_buf, obj_buf_sz);
if (ret != TEST_OK)
pr_debug("Failed to parse test case '%s'\n",
bpf_source_table[i].desc);
}
free(obj_buf);
switch (ret) {
case TEST_SKIP:
return TEST_SKIP;
case TEST_OK:
break;
default:
/*
* Test 0 is the basic LLVM test. If test 0
* fail, the basic LLVM support not functional
* so the whole test should fail. If other test
* case fail, it can be fixed by adjusting
* config so don't report error.
*/
if (i == 0)
return TEST_FAIL;
else
return TEST_SKIP;
}
}
return TEST_OK;
}

16
tools/perf/tests/llvm.h Normal file
View File

@ -0,0 +1,16 @@
#ifndef PERF_TEST_LLVM_H
#define PERF_TEST_LLVM_H
#include <stddef.h> /* for size_t */
#include <stdbool.h> /* for bool */
extern const char test_llvm__bpf_base_prog[];
enum test_llvm__testcase {
LLVM_TESTCASE_BASE,
__LLVM_TESTCASE_MAX,
};
int test_llvm__fetch_bpf_obj(void **p_obj_buf, size_t *p_obj_buf_sz,
enum test_llvm__testcase index, bool force);
#endif