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snooper: Add testing "app" for task_work-based demo
Signed-off-by: Andrii Nakryiko <[email protected]>
1 parent 8f9cb1e commit d44b383

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5 files changed

+164
-3
lines changed

5 files changed

+164
-3
lines changed

‎examples/c/.gitignore‎

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@@ -16,5 +16,7 @@
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/lsm
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/cmake-build-debug/
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/cmake-build-release/
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/snooper
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compile_commands.json
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/app
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/libapp.so
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/snooper

‎examples/c/Makefile‎

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@@ -70,12 +70,12 @@ $(call allow-override,CC,$(CROSS_COMPILE)cc)
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$(call allow-override,LD,$(CROSS_COMPILE)ld)
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.PHONY: all
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all: $(APPS)
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all: $(APPS) app
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.PHONY: clean
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clean:
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$(call msg,CLEAN)
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$(Q)rm -rf $(OUTPUT) $(APPS)
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$(Q)rm -rf $(OUTPUT) $(APPS) app libapp.so
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$(OUTPUT) $(OUTPUT)/libbpf $(BPFTOOL_OUTPUT):
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$(call msg,MKDIR,$@)
@@ -136,3 +136,12 @@ $(APPS): %: $(OUTPUT)/%.o $(LIBBPF_OBJ) | $(OUTPUT)
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# keep intermediate (.skel.h, .bpf.o, etc) targets
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.SECONDARY:
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# Build target app and its shared library
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libapp.so: app_lib.c app_lib.h
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$(call msg,SHLIB,$@)
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$(Q)$(CC) $(CFLAGS) -shared -fPIC -o $@ app_lib.c
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app: app.c app_lib.h libapp.so
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$(call msg,BINARY,$@)
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$(Q)$(CC) $(CFLAGS) -o $@ app.c -L. -lapp -Wl,-rpath,'$$ORIGIN' -lpthread

‎examples/c/app.c‎

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#define _GNU_SOURCE
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#include <stdio.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <errno.h>
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#include <string.h>
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#include <stdlib.h>
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#include <dlfcn.h>
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#include <elf.h>
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#include <pthread.h>
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#include "app_lib.h"
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static __thread int tls_dont_care; /* just to avoid zero offsets everywhere else */
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__thread int tls_exec;
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extern __thread int tls_shared;
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static __thread int tls_local_exec;
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int __attribute__((weak)) get_tls_exec(void)
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{
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return tls_exec;
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}
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int __attribute__((weak)) get_tls_shared(void)
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{
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return tls_shared;
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}
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int __attribute__((weak)) get_tls_local_exec(void)
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{
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return tls_local_exec;
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}
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/* Forward declarations for recursive functions */
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void func_a(int depth);
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void func_b(int depth);
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void func_c(int depth);
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static __always_inline void func_mux(int depth)
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{
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if (depth <= 0)
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return;
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switch (rand() % 3) {
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case 0: func_a(depth - 1); break;
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case 1: func_b(depth - 1); break;
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case 2: func_c(depth - 1); break;
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}
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}
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void func_a(int depth)
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{
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volatile char stack_space[120];
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stack_space[119] = 'a';
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stack_space[0] += 1;
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if (depth <= 0)
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return;
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func_mux(depth - 1);
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}
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void func_b(int depth)
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{
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volatile char stack_space[350];
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stack_space[349] = 'b';
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stack_space[0] += 1;
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if (depth <= 0)
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return;
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func_mux(depth - 1);
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}
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void func_c(int depth)
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{
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volatile char stack_space[800];
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stack_space[799] = 'c';
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stack_space[0] += 1;
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if (depth <= 0)
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return;
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func_mux(depth - 1);
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}
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static void *thread_func(void *arg)
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{
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time_t last_print = 0;
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(void)arg;
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pthread_setname_np(pthread_self(), "app_thread");
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while (1) {
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time_t now;
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func_mux(10);
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now = time(NULL);
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if (now > last_print) {
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tls_exec += 4;
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tls_shared += 8;
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tls_local_exec += 16;
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bump_tls_local_shared();
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bump_tls_local_shared();
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printf("Hello from thread (exec=%d, shared=%d, local_exec=%d, local_shared=%d)!\n",
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get_tls_exec(), get_tls_shared(), get_tls_local_exec(), get_tls_local_shared());
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last_print = now;
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}
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}
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return NULL;
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}
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int main() {
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pthread_t thread;
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pthread_create(&thread, NULL, thread_func, NULL);
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while (1) {
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tls_dont_care += 1;
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tls_exec += 2;
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tls_shared += 4;
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tls_local_exec += 8;
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bump_tls_local_shared();
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printf("Hello from app (exec=%d, shared=%d, local_exec=%d, local_shared=%d)!\n",
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get_tls_exec(), get_tls_shared(), get_tls_local_exec(), get_tls_local_shared());
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sleep(1);
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}
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return 0;
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}

‎examples/c/app_lib.c‎

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__thread int tls_shared;
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static __thread int tls_local_shared;
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int get_tls_local_shared(void) { return tls_local_shared; }
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void bump_tls_local_shared(void) { tls_local_shared += 16; }

‎examples/c/app_lib.h‎

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#ifndef APP_LIB_H
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#define APP_LIB_H
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int get_tls_local_shared(void);
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void bump_tls_local_shared(void);
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#endif /* APP_LIB_H */

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