support chain function calling by introducing hashtable for retrieving module struct

runtime/Makefile

@@ -10,10 +10,10 @@ PAGE_SIZE := $(shell getconf PAGESIZE)
 
 # Compiler Settings
 CC=clang
-CC_OPTIONS = -O3 -flto -g -pthread -D_GNU_SOURCE
+#CC_OPTIONS = -O3 -flto -g -pthread -D_GNU_SOURCE
 
 # CC_OPTIONS for Debugging
-# CC_OPTIONS = -O0 -g -pthread -D_GNU_SOURCE
+CC_OPTIONS = -O0 -g -pthread -D_GNU_SOURCE
 
 # CFI Sanitizer
 # CC_OPTIONS = -O0 -g -pthread -D_GNU_SOURCE -flto -fvisibility=default -fsanitize=cfi 
@@ -91,6 +91,7 @@ CFLAGS += -DUSE_MEM_VM
 LDFLAGS += -Wl,--export-dynamic -ldl -lm
 LDFLAGS += -Lthirdparty/dist/lib/
 INCLUDES += -Iinclude/ -Ithirdparty/dist/include/
+INCLUDES += -Iinclude/ -Ithirdparty/ck/include/
 
 # CFILES
 CFILES += src/*.c
@@ -99,6 +100,7 @@ CFILES += src/libc/*.c
 CFILES += src/memory/common.c
 CFILES += src/memory/64bit_nix.c
 CFILES += thirdparty/dist/lib/http_parser.o
+CFILES += thirdparty/dist/lib/libck.a
 
 # Configuring Jasmine
 JSMNCFLAGS += -DJSMN_STATIC

runtime/include/arch/aarch64/context.h

@@ -41,7 +41,7 @@ arch_context_init(struct arch_context *actx, reg_t ip, reg_t sp)
  * which defaults to resuming execution of main
  */
 static inline int
-arch_context_switch(struct arch_context *a, struct arch_context *b)
+arch_context_switch(struct arch_context *a, struct arch_context *b) //save context to a and switch to context b
 {
 #ifndef NDEBUG
 	/*
@@ -61,7 +61,7 @@ arch_context_switch(struct arch_context *a, struct arch_context *b)
 	assert(a != b);
 
 	/* Set any NULLs to worker_thread_base_context to resume execution of main */
-	if (a == NULL) a = &worker_thread_base_context;
+	if (a == NULL) a = &worker_thread_base_context; //NULL indicates the main context of the worker thread before running any sandboxs
 	if (b == NULL) b = &worker_thread_base_context;
 
 	/* A Transition {Unused, Running} -> Fast */

runtime/include/arch/x86_64/context.h

@@ -80,6 +80,8 @@ arch_context_restore_new(mcontext_t *active_context, struct arch_context *sandbo
  *
  * NULL in either of these values indicates the "no sandbox to execute" state,
  * which defaults to resuming execution of main
+ * save the current context to a, and switch to b, if b is fast path, then only restore b's IP 
+ * and SP; if b is slow path, then send a SIGUSER1 to restore a full context of b
  */
 static inline int
 arch_context_switch(struct arch_context *a, struct arch_context *b)

runtime/include/module_manager.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include "module.h"
+#include "ck_ht.h" 
+
+extern ck_ht_t g_module_ht;
+extern void init_module_ht();
+extern void insert_module_to_ht(const uint32_t port, const struct module* module);
+extern struct module* get_module_from_ht(const uint32_t port);

runtime/include/sandbox_functions.h

@@ -28,6 +28,16 @@ sandbox_close_http(struct sandbox *sandbox)
 	client_socket_close(sandbox->client_socket_descriptor, &sandbox->client_address);
 }
 
+static inline void
+sandbox_remove_from_epoll(struct sandbox *sandbox)
+{
+        assert(sandbox != NULL);
+
+        int rc = epoll_ctl(worker_thread_epoll_file_descriptor, EPOLL_CTL_DEL, sandbox->client_socket_descriptor, NULL);
+        if (unlikely(rc < 0)) panic_err();
+
+}
+
 /**
  * Initializes a sandbox fd ready for use with the proper preopen magic
  * @param sandbox
@@ -133,7 +143,7 @@ sandbox_open_http(struct sandbox *sandbox)
 	http_parser_init(&sandbox->http_parser, HTTP_REQUEST);
 
 	/* Set the sandbox as the data the http-parser has access to */
-	sandbox->http_parser.data = sandbox;
+	sandbox->http_parser.data = sandbox; //assign data to sandbox in case to operator it when a callback happended
 
 	/* Freshly allocated sandbox going runnable for first time, so register client socket with epoll */
 	struct epoll_event accept_evt;

runtime/include/sandbox_request.h

@@ -15,13 +15,17 @@
 
 struct sandbox_request {
 	uint64_t        id;
+	bool		request_from_outside; /* true is yes, false is no */
+	int current_func_index;
 	struct module * module;
 	char *          arguments;
 	int             socket_descriptor;
 	struct sockaddr socket_address;
 	uint64_t        request_arrival_timestamp; /* cycles */
 	uint64_t        absolute_deadline;         /* cycles */
-
+	char * previous_function_output;
+	ssize_t output_length;
+	ssize_t pre_request_length;                    /* previous request length */
 	/*
 	 * Unitless estimate of the instantaneous fraction of system capacity required to run the request
 	 * Calculated by estimated execution time (cycles) * runtime_admissions_granularity / relative deadline (cycles)
@@ -65,9 +69,10 @@ sandbox_request_log_allocation(struct sandbox_request *sandbox_request)
  * @return the new sandbox request
  */
 static inline struct sandbox_request *
-sandbox_request_allocate(struct module *module, char *arguments, int socket_descriptor,
+sandbox_request_allocate(struct module *module, bool request_from_outside, ssize_t request_length, int current_func_index, 
+			 char *arguments, int socket_descriptor,
                          const struct sockaddr *socket_address, uint64_t request_arrival_timestamp,
-                         uint64_t admissions_estimate)
+                         uint64_t admissions_estimate, char *previous_function_output, ssize_t output_length)
 {
 	struct sandbox_request *sandbox_request = (struct sandbox_request *)malloc(sizeof(struct sandbox_request));
 	assert(sandbox_request);
@@ -76,11 +81,16 @@ sandbox_request_allocate(struct module *module, char *arguments, int socket_desc
 	sandbox_request->id = sandbox_request_count_postfix_increment();
 
 	sandbox_request->module            = module;
+	sandbox_request->request_from_outside = request_from_outside;
+	sandbox_request->current_func_index = current_func_index;
 	sandbox_request->arguments         = arguments;
 	sandbox_request->socket_descriptor = socket_descriptor;
 	memcpy(&sandbox_request->socket_address, socket_address, sizeof(struct sockaddr));
 	sandbox_request->request_arrival_timestamp = request_arrival_timestamp;
 	sandbox_request->absolute_deadline         = request_arrival_timestamp + module->relative_deadline;
+	sandbox_request->previous_function_output = previous_function_output;
+	sandbox_request->output_length = output_length;
+	sandbox_request->pre_request_length = request_length;
 
 	/*
 	 * Admissions Control State

runtime/include/sandbox_set_as_initialized.h

@@ -33,6 +33,11 @@ sandbox_set_as_initialized(struct sandbox *sandbox, struct sandbox_request *sand
 	sandbox->allocation_timestamp      = allocation_timestamp;
 	sandbox->state                     = SANDBOX_SET_AS_INITIALIZED;
 
+	sandbox->current_func_index = sandbox_request->current_func_index;
+	sandbox->request_from_outside = sandbox_request->request_from_outside;
+	sandbox->previous_function_output = sandbox_request->previous_function_output;
+	sandbox->output_length = sandbox_request->output_length;
+	sandbox->pre_request_length = sandbox_request->pre_request_length;
 	/* Initialize the sandbox's context, stack, and instruction pointer */
 	/* stack_start points to the bottom of the usable stack, so add stack_size to get to top */
 	arch_context_init(&sandbox->ctxt, (reg_t)current_sandbox_start,

runtime/include/sandbox_types.h

@@ -31,6 +31,11 @@ struct sandbox_io_handle {
 
 struct sandbox {
 	uint64_t        id;
+	bool request_from_outside;
+	int current_func_index; /* indicate the index of next function in the chain */
+	char * previous_function_output; /* the output of the previous function */
+	ssize_t output_length; /* the length of previous_function_output */
+	ssize_t pre_request_length; /* the length of previous_function_output */
 	sandbox_state_t state;
 
 	uint32_t sandbox_size; /* The struct plus enough buffer to hold the request or response (sized off largest) */

runtime/include/workflow.h

@@ -0,0 +1,4 @@
+#pragma once
+
+extern unsigned short g_single_function_flow_table[];
+extern int g_chain_length;

runtime/src/current_sandbox.c

@@ -6,6 +6,9 @@
 #include "sandbox_set_as_returned.h"
 #include "sandbox_setup_arguments.h"
 #include "scheduler.h"
+#include "workflow.h"
+#include "module.h"
+#include "module_manager.h"
 #include "software_interrupt.h"
 
 __thread struct sandbox *worker_thread_current_sandbox = NULL;
@@ -68,19 +71,32 @@ current_sandbox_start(void)
 
 	sandbox_initialize_stdio(sandbox);
 
-	sandbox_open_http(sandbox);
-
-	if (sandbox_receive_request(sandbox) < 0) {
-		error_message = "Unable to receive or parse client request\n";
-		goto err;
-	};
+	sandbox_open_http(sandbox);//add IN/OUT event to epoll
+
+	if (sandbox->request_from_outside) {
+		if (sandbox_receive_request(sandbox) < 0) {//read data from client socket to get http request, 
+						           //the result populates http_request structure
+						   	   // if read blocked, then remove the sandbox from the 
+						   	   // local runqueue and pause the sandbox
+			error_message = "Unable to receive or parse client request\n";
+			goto err;
+		};
+	} else {
+		// copy previous output to sandbox->request_response_data, as the input for the sandbox.
+		// let sandbox->http_request->body points to sandbox->request_response_data
+		assert(sandbox->previous_function_output != NULL);
+		memcpy(sandbox->request_response_data, sandbox->previous_function_output, sandbox->output_length);
+		sandbox->http_request.body = sandbox->request_response_data;
+		sandbox->http_request.body_length = sandbox->output_length;	
+		sandbox->request_length = sandbox->pre_request_length;
+		sandbox->request_response_data_length = sandbox->request_length;
+	}
 
 	/* Initialize sandbox memory */
 	struct module *current_module = sandbox_get_module(sandbox);
 	module_initialize_globals(current_module);
 	module_initialize_memory(current_module);
-	sandbox_setup_arguments(sandbox);
-
+	sandbox_setup_arguments(sandbox); //this arguments is not the http body content
 	/* Executing the function */
 	int32_t argument_count = module_get_argument_count(current_module);
 	current_sandbox_enable_preemption(sandbox);
@@ -88,24 +104,49 @@ current_sandbox_start(void)
 	current_sandbox_disable_preemption(sandbox);
 	sandbox->completion_timestamp = __getcycles();
 
-	/* Retrieve the result, construct the HTTP response, and send to client */
-	if (sandbox_send_response(sandbox) < 0) {
-		error_message = "Unable to build and send client response\n";
-		goto err;
-	};
-
-	http_total_increment_2xx();
-
-	sandbox->response_timestamp = __getcycles();
-
-	assert(sandbox->state == SANDBOX_RUNNING);
-	sandbox_close_http(sandbox);
-	sandbox_set_as_returned(sandbox, SANDBOX_RUNNING);
 
+	if (sandbox->current_func_index + 1 < g_chain_length) {
+		uint32_t next_port = g_single_function_flow_table[sandbox->current_func_index + 1];
+		struct module * next_module = get_module_from_ht(next_port);
+		assert(next_module != NULL); 
+		//generate a new request, copy the current sandbox's output to the next request's buffer, and put it to the global queue
+		
+		ssize_t output_length = sandbox->request_response_data_length - sandbox->request_length;
+		char * pre_func_output = (char *) malloc(output_length);
+		memcpy(pre_func_output, sandbox->request_response_data + sandbox->request_length, output_length);
+		struct sandbox_request *sandbox_request =
+                                  sandbox_request_allocate(next_module, false, sandbox->request_length, sandbox->current_func_index + 1, 
+							   next_module->name, sandbox->client_socket_descriptor,
+                                                           (const struct sockaddr *)&sandbox->client_address,
+                                                           sandbox->request_arrival_timestamp, true, pre_func_output, output_length);
+                /* Add to the Global Sandbox Request Scheduler */
+                global_request_scheduler_add(sandbox_request);
+		sandbox_remove_from_epoll(sandbox);
+		sandbox_set_as_returned(sandbox, SANDBOX_RUNNING);
+		scheduler_yield();
+		assert(0); 
+		return;
+	} else {
+		/* Retrieve the result, construct the HTTP response, and send to client */
+		if (sandbox_send_response(sandbox) < 0) { // if send blocked, remove the sandbox from the local runqueue
+						  // and pause the sandbox
+			error_message = "Unable to build and send client response\n";
+			goto err;
+		};
+
+		http_total_increment_2xx();
+
+		sandbox->response_timestamp = __getcycles();
+
+		assert(sandbox->state == SANDBOX_RUNNING);
+		sandbox_close_http(sandbox);
+		sandbox_set_as_returned(sandbox, SANDBOX_RUNNING); //request is completed, remove the sandbox from the
+							   //local runqueue
+	}
 done:
 	/* Cleanup connection and exit sandbox */
 	generic_thread_dump_lock_overhead();
-	scheduler_yield();
+	scheduler_yield(); //put the sandbox to the complete queue
 
 	/* This assert prevents a segfault discussed in
 	 * https://github.com/phanikishoreg/awsm-Serverless-Framework/issues/66

runtime/src/global_request_scheduler_minheap.c

@@ -19,7 +19,7 @@ global_request_scheduler_minheap_add(void *sandbox_request)
 {
 	assert(sandbox_request);
 	assert(global_request_scheduler_minheap);
-	if (unlikely(!listener_thread_is_running())) panic("%s is only callable by the listener thread\n", __func__);
+	//if (unlikely(!listener_thread_is_running())) panic("%s is only callable by the listener thread\n", __func__);
 
 	int return_code = priority_queue_enqueue(global_request_scheduler_minheap, sandbox_request);
 	/* TODO: Propagate -1 to caller. Issue #91 */
@@ -75,7 +75,7 @@ sandbox_request_get_priority_fn(void *element)
  */
 void
 global_request_scheduler_minheap_initialize()
-{
+{       /* second parameter is set to true, means we will use lock for this queue since it is a global queue shared by all worker threads */
 	global_request_scheduler_minheap = priority_queue_initialize(4096, true, sandbox_request_get_priority_fn);
 
 	struct global_request_scheduler_config config = {

runtime/src/listener_thread.c

@@ -177,9 +177,9 @@ listener_thread_main(void *dummy)
 
 				/* Allocate a Sandbox Request */
 				struct sandbox_request *sandbox_request =
-				  sandbox_request_allocate(module, module->name, client_socket,
+				  sandbox_request_allocate(module, true, 0, 0, module->name, client_socket,
 				                           (const struct sockaddr *)&client_address,
-				                           request_arrival_timestamp, work_admitted);
+				                           request_arrival_timestamp, work_admitted, NULL, 0);
 
 				/* Add to the Global Sandbox Request Scheduler */
 				global_request_scheduler_add(sandbox_request);

runtime/src/module.c

@@ -12,6 +12,7 @@
 #include "likely.h"
 #include "listener_thread.h"
 #include "module.h"
+#include "module_manager.h"
 #include "module_database.h"
 #include "panic.h"
 #include "runtime.h"
@@ -560,6 +561,7 @@ module_new_from_json(char *file_name)
 			module_set_http_info(module, request_count, request_headers, request_content_type,
 			                     response_count, reponse_headers, response_content_type);
 			module_count++;
+			insert_module_to_ht((uint32_t)port, module);
 		}
 
 		free(request_headers);

runtime/src/module_manager.c

@@ -0,0 +1,104 @@
+#include "module_manager.h"
+
+ck_ht_t g_module_ht;
+
+static void *
+ht_malloc(size_t r)
+{
+
+        return malloc(r);
+}
+
+static void
+ht_free(void *p, size_t b, bool r)
+{
+
+        (void)b;
+        (void)r;
+        free(p);
+        return;
+}
+
+static void
+ht_hash_wrapper(struct ck_ht_hash *h,
+        const void *key,
+        size_t length,
+        uint64_t seed)
+{
+        //h->value = (unsigned long)MurmurHash64A(key, length, seed);
+        return;
+}
+
+static struct ck_malloc my_allocator = {
+        .malloc = ht_malloc,
+        .free = ht_free
+};
+
+/**
+ * Module Manager Hashtable initilization Function
+ * Initilize the glaoble hashtable g_module_ht
+ * Returns true if initlization success, false otherwise
+ */
+
+void 
+init_module_ht()
+{
+	if (ck_ht_init(&g_module_ht, CK_HT_MODE_DIRECT, NULL, &my_allocator, 2, 6602834) == false) {
+                perror("ck_ht_init");
+                exit(EXIT_FAILURE);
+        }
+
+}
+/**
+ * Module Manager Insert Function
+ * Insert a module with a key into a hashtable, the key is the port number.
+ * The value is the module object pointer
+ *
+ * @param port - the TCP port number that the module will listen to
+ * @param module - the module object pointer that will be inserted into the hashtable
+ */
+
+void 
+insert_module_to_ht(const uint32_t port, const struct module* module) 
+{
+	assert(module != NULL);
+	ck_ht_entry_t entry;
+	ck_ht_hash_t h;
+        ck_ht_hash_direct(&h, &g_module_ht, (uintptr_t)port);	
+	ck_ht_entry_set_direct(&entry, h, (uintptr_t)port, (uintptr_t)module);
+	ck_ht_put_spmc(&g_module_ht, h, &entry);
+	printf("insert port %u, module=%p\n", port, module);
+}
+
+/**
+ * Module Manager Get Function
+ * Get a module from the hashtable with a key, the key is the port number.
+ * Returns the module object pointer 
+ *
+ */
+
+struct module* 
+get_module_from_ht(const uint32_t port)
+{
+	printf("try to get module with port %u\n", port);
+	ck_ht_entry_t entry;
+        ck_ht_hash_t h;
+	ck_ht_hash_direct(&h, &g_module_ht, (uintptr_t)port);
+	ck_ht_entry_key_set_direct(&entry, (uintptr_t)port);
+	if (ck_ht_get_spmc(&g_module_ht, h, &entry) == false) { //
+                printf("ERROR: Found non-existing entry with port %u.\n", port);
+		return NULL;
+        }
+	uintptr_t k, v;
+
+        k = ck_ht_entry_key_direct(&entry);// get key from entry
+        v = ck_ht_entry_value_direct(&entry);//get value from entry
+	if (unlikely(k != port)) {
+		printf("ERROR: key doesnt match with port %u.\n", port);
+		return NULL;
+	} else {
+		printf("module found, address is =%p\n", v);
+		return (struct module*) v;	
+	}
+}
+

runtime/src/runtime.c

@@ -19,6 +19,7 @@
 #include "http_parser_settings.h"
 #include "listener_thread.h"
 #include "module.h"
+#include "module_manager.h"
 #include "runtime.h"
 #include "sandbox_request.h"
 #include "scheduler.h"
@@ -65,12 +66,12 @@ runtime_set_resource_limits_to_max()
 		int resource = resources[i];
 		if (getrlimit(resource, &limit) < 0) panic_err();
 
-		if (limit.rlim_cur == RLIM_INFINITY) {
+		if (limit.rlim_cur == RLIM_INFINITY) { // rlim_cur is soft limit
 			strncpy(lim, "Infinite", uint64_t_max_digits);
 		} else {
 			snprintf(lim, uint64_t_max_digits, "%lu", limit.rlim_cur);
 		}
-		if (limit.rlim_max == RLIM_INFINITY) {
+		if (limit.rlim_max == RLIM_INFINITY) { // rlim_max is hard limit
 			strncpy(max, "Infinite", uint64_t_max_digits);
 		} else {
 			snprintf(max, uint64_t_max_digits, "%lu", limit.rlim_max);
@@ -91,18 +92,21 @@ runtime_set_resource_limits_to_max()
 void
 runtime_initialize(void)
 {
-	http_total_init();
-	sandbox_request_count_initialize();
-	sandbox_count_initialize();
+	http_total_init(); //initilize http requests/error response counter
+	sandbox_request_count_initialize(); //initilize sandbox requests counter
+	sandbox_count_initialize(); //initilize sandbox state counter
 
 	/* Setup Scheduler */
-	scheduler_initialize();
+	scheduler_initialize(); //set function pointers to global_request_scheduler, both EDF and FIFO have a set of functions
 
+	/* Init global module hash table */
+	init_module_ht();
 	/* Configure Signals */
-	signal(SIGPIPE, SIG_IGN);
-	signal(SIGTERM, runtime_cleanup);
+	signal(SIGPIPE, SIG_IGN); // ignore SIGPIPE
+	signal(SIGTERM, runtime_cleanup); // call runtime_cleanup when get SIGTERM signal
 
-	http_parser_settings_initialize();
+	http_parser_settings_initialize(); // set function pointers for http parser lib, when get a http message, some callback
+					   // functions will be called
 	admissions_control_initialize();
 }
 

runtime/src/sandbox.c

@@ -186,9 +186,12 @@ sandbox_free(struct sandbox *sandbox)
 	assert(sandbox->state == SANDBOX_ERROR || sandbox->state == SANDBOX_COMPLETE);
 
 	int rc;
+	if (sandbox->previous_function_output != NULL) {
+		free(sandbox->previous_function_output);
+		sandbox->previous_function_output = NULL;
+	}
 
 	module_release(sandbox->module);
-
 	/* Free Sandbox Stack */
 	errno = 0;
 

runtime/src/workflow.c

@@ -0,0 +1,6 @@
+#include "workflow.h"
+
+unsigned short g_single_function_flow_table[] = {10000, 10001};
+int g_chain_length = 2;
+int g_execution_index = 0;
+

runtime/tests/Makefile.inc

@@ -3,8 +3,8 @@ ARCH := $(shell uname -m)
 CC=clang # Source -> Native
 WASMCC=wasm32-unknown-unknown-wasm-clang # Source -> WebAssembly
 
-OPTFLAGS=-O3 -flto
-# OPTFLAGS=-O0 -flto -g
+# OPTFLAGS=-O3 -flto
+OPTFLAGS=-O0 -flto -g
 MEMC_64=64bit_nix.c
 # MEMC_NO=no_protection.c
 # MEMC_GEN=generic.c

runtime/tests/debug.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+# Executes the runtime in GDB
+# Substitutes the absolute path from the container with a path relatively derived from the location of this script
+# This allows debugging outside of the Docker container
+# Also disables pagination and stopping on SIGUSR1
+
+declare project_path="$(
+	cd "$(dirname "$1")/../.."
+	pwd
+)"
+echo $project_path
+cd ../../bin
+export LD_LIBRARY_PATH="$(pwd):$LD_LIBRARY_PATH"
+gdb --eval-command="handle SIGUSR1 nostop" \
+	--eval-command="set pagination off" \
+	--eval-command="set substitute-path /sledge/runtime $project_path" \
+	--eval-command="run ../tests/my_fibonacci.json" \
+	./sledgert
+cd ../../tests

runtime/tests/my_fibonacci.json

@@ -0,0 +1,30 @@
+{
+  "active": true,
+  "name": "fibonacci",
+  "path": "fibonacci_wasm.so",
+  "port": 10000,
+  "expected-execution-us": 600,
+  "relative-deadline-us": 2000,
+  "argsize": 2,
+  "http-req-headers": [],
+  "http-req-content-type": "text/plain",
+  "http-req-size": 1024,
+  "http-resp-headers": [],
+  "http-resp-size": 1024,
+  "http-resp-content-type": "text/plain"
+},
+{
+  "active": true,
+  "name": "fibonacci",
+  "path": "fibonacci_wasm.so",
+  "port": 10001,
+  "expected-execution-us": 600,
+  "relative-deadline-us": 2000,
+  "argsize": 2,
+  "http-req-headers": [],
+  "http-req-content-type": "text/plain",
+  "http-req-size": 1024,
+  "http-resp-headers": [],
+  "http-resp-size": 1024,
+  "http-resp-content-type": "text/plain"
+}