Merge #835

835: Add parallel execution example r=Hywan a=MarkMcCaskey

A bit wip

# Review

- [x] Add a short description of the the change to the CHANGELOG.md file


Co-authored-by: Mark McCaskey <[email protected]>

CHANGELOG.md

@@ -6,9 +6,11 @@ Blocks of changes will separated by version increments.
 
 ## **[Unreleased]**
 
-- [#835](https://github.com/wasmerio/wasmer/pull/836) Update Cranelift fork version to `0.44.0`
+- [#836](https://github.com/wasmerio/wasmer/pull/836) Update Cranelift fork version to `0.44.0`
 - [#839](https://github.com/wasmerio/wasmer/pull/839) Change supported version to stable Rust 1.37+
 - [#834](https://github.com/wasmerio/wasmer/pull/834) Fix panic when unwraping `wasmer` arguments
+- [#835](https://github.com/wasmerio/wasmer/pull/835) Add parallel execution example (independent instances created from the same `ImportObject` and `Module` run with rayon)
+- [#834](https://github.com/wasmerio/wasmer/pull/834) Fix panic when parsing numerical arguments for no-ABI targets run with the wasmer binary
 - [#833](https://github.com/wasmerio/wasmer/pull/833) Add doc example of using ImportObject's new `maybe_with_namespace` method
 - [#832](https://github.com/wasmerio/wasmer/pull/832) Delete unused runtime ABI
 - [#809](https://github.com/wasmerio/wasmer/pull/809) Fix bugs leading to panics in `LocalBacking`.

Cargo.toml

@@ -57,6 +57,8 @@ members = [
     "lib/emscripten-tests",
     "lib/middleware-common-tests",
     "examples/plugin-for-example",
+    "examples/parallel",
+    "examples/parallel-guest",
 ]
 
 [build-dependencies]

examples/parallel-guest/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "parallel-guest"
+version = "0.1.0"
+authors = ["The Wasmer Engineering Team <[email protected]>"]
+license = "MIT"
+edition = "2018"
+publish = false
+
+[dependencies]
+md5 = "0.6"
+lazy_static = "1"

examples/parallel-guest/src/main.rs

@@ -0,0 +1,82 @@
+#[macro_use]
+extern crate lazy_static;
+
+extern "C" {
+    fn get_hashed_password(ptr: u32, len: u32) -> u32;
+    fn print_char(c: u32);
+}
+
+fn print_str(s: &str) {
+    for c in s.chars() {
+        unsafe { print_char(c as u32) };
+    }
+    unsafe { print_char(b'\n' as u32) };
+}
+
+fn load_hashed_password() -> Option<String> {
+    let mut buffer = String::with_capacity(32);
+    for _ in 0..32 {
+        buffer.push(0 as char);
+    }
+    let result =
+        unsafe { get_hashed_password(buffer.as_mut_ptr() as u32, buffer.capacity() as u32) };
+
+    if result == 0 {
+        Some(buffer)
+    } else {
+        None
+    }
+}
+
+lazy_static! {
+    static ref HASHED_PASSWORD: String = load_hashed_password().unwrap();
+}
+
+static PASSWORD_CHARS: &'static [u8] = b"abcdefghijklmnopqrstuvwxyz0123456789";
+
+// for simplicty we define a scheme for mapping numbers onto passwords
+fn num_to_password(mut num: u64) -> String {
+    let mut extra_zero = num == 0;
+    let mut out = String::new();
+    while num > 0 {
+        out.push(PASSWORD_CHARS[num as usize % PASSWORD_CHARS.len()] as char);
+        extra_zero = extra_zero || num == PASSWORD_CHARS.len() as u64;
+        num /= PASSWORD_CHARS.len() as u64;
+    }
+
+    if extra_zero {
+        out.push(PASSWORD_CHARS[0] as char);
+    }
+
+    out
+}
+
+#[repr(C)]
+struct RetStr {
+    ptr: u32,
+    len: u32,
+}
+
+// returns a (pointer, len) to the password or null
+#[no_mangle]
+fn check_password(from: u64, to: u64) -> u64 {
+    for i in from..to {
+        let password = num_to_password(i);
+        let digest = md5::compute(&password);
+
+        let hash_as_str = format!("{:x}", digest);
+        if hash_as_str == *HASHED_PASSWORD {
+            let ret = RetStr {
+                ptr: password.as_ptr() as usize as u32,
+                len: password.len() as u32,
+            };
+            // leak the data so ending the function doesn't corrupt it, if we cared the host could free it after
+            std::mem::forget(password);
+            return unsafe { std::mem::transmute(ret) };
+        }
+    }
+
+    return 0;
+}
+
+fn main() {}

examples/parallel/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "parallel"
+version = "0.1.0"
+authors = ["The Wasmer Engineering Team <[email protected]>"]
+edition = "2018"
+repository = "https://github.com/wasmerio/wasmer"
+publish = false
+license = "MIT"
+
+[dependencies]
+rayon = "1.2"
+time = "0.1"
+wasmer-runtime = { path = "../../lib/runtime" }
+wasmer-runtime-core = { path = "../../lib/runtime-core" }

examples/parallel/README.md

@@ -0,0 +1,5 @@
+# Parallel Wasmer example
+
+This example shows executing independent code from multiple threads on an "embarassingly parallel" problem
+
+This is a toy example of cracking md5 hashes.  This is not a benchmark.  This example is not optimized, it will compare poorly to an implementation that is.

examples/parallel/src/main.rs

@@ -0,0 +1,137 @@
+use rayon::prelude::*;
+use wasmer_runtime::{compile_with, compiler_for_backend, func, imports, instantiate, Backend};
+use wasmer_runtime_core::{
+    memory::ptr::{Array, WasmPtr},
+    vm::Ctx,
+};
+
+static PLUGIN_LOCATION: &'static str = "../parallel-guest.wasm";
+
+fn get_hashed_password(ctx: &mut Ctx, ptr: WasmPtr<u8, Array>, len: u32) -> u32 {
+    // "hard" password - 7 characters
+    //let password = b"2ab96390c7dbe3439de74d0c9b0b1767";
+    // "easy" password - 5 characters
+    let password = b"ab56b4d92b40713acc5af89985d4b786";
+    let memory = ctx.memory(0);
+    if let Some(writer) = ptr.deref(memory, 0, len) {
+        for (i, byte) in password.iter().enumerate() {
+            writer[i].set(*byte)
+        }
+
+        0
+    } else {
+        u32::max_value()
+    }
+}
+
+#[repr(C)]
+struct RetStr {
+    ptr: u32,
+    len: u32,
+}
+
+fn print_char(_cxt: &mut Ctx, c: u32) {
+    print!("{}", c as u8 as char);
+}
+
+fn main() {
+    let wasm_bytes = std::fs::read(PLUGIN_LOCATION).expect(&format!(
+        "Could not read in WASM plugin at {}",
+        PLUGIN_LOCATION
+    ));
+
+    let imports = imports! {
+        "env" => {
+            "get_hashed_password" => func!(get_hashed_password),
+            "print_char" => func!(print_char),
+        },
+    };
+    let compiler = compiler_for_backend(Backend::default()).unwrap();
+    let module = compile_with(&wasm_bytes[..], compiler.as_ref()).unwrap();
+
+    println!("Parallel");
+    let start_ts = time::SteadyTime::now();
+    for outer in 0..1000u64 {
+        let start = outer * 1000;
+        let end = start + 1000;
+        let out = (start..=end)
+            .into_par_iter()
+            .filter_map(|i| {
+                let instance = module
+                    .clone()
+                    .instantiate(&imports)
+                    .expect("failed to instantiate wasm module");
+                let check_password = instance.func::<(u64, u64), u64>("check_password").unwrap();
+                let j = i * 10000;
+                let result = check_password.call(j, j + 10000).unwrap();
+                print!(".");
+                use std::io::Write;
+                std::io::stdout().flush().unwrap();
+                if result != 0 {
+                    let res: RetStr = unsafe { std::mem::transmute(result) };
+
+                    let ctx = instance.context();
+                    let memory = ctx.memory(0);
+                    let wasm_ptr: WasmPtr<u8, Array> = WasmPtr::new(res.ptr);
+                    let password_str = wasm_ptr
+                        .get_utf8_string(memory, res.len)
+                        .unwrap()
+                        .to_string();
+                    Some(password_str)
+                } else {
+                    None
+                }
+            })
+            .find_first(|_: &String| true);
+        if out.is_some() {
+            let end_ts = time::SteadyTime::now();
+            let delta = end_ts - start_ts;
+            println!(
+                "Password cracked: \"{}\" in {}.{:03}",
+                out.unwrap(),
+                delta.num_seconds(),
+                (delta.num_milliseconds() % 1000),
+            );
+            break;
+        }
+    }
+
+    println!("Serial:");
+    let start_ts = time::SteadyTime::now();
+    let instance =
+        instantiate(&wasm_bytes[..], &imports).expect("failed to instantiate wasm module");
+
+    let check_password = instance.func::<(u64, u64), u64>("check_password").unwrap();
+
+    let mut out: Option<RetStr> = None;
+    for i in (0..=u64::max_value()).step_by(10000) {
+        let result = check_password.call(i, i + 10000).unwrap();
+        print!(".");
+        use std::io::Write;
+        std::io::stdout().flush().unwrap();
+        if result != 0 {
+            out = Some(unsafe { std::mem::transmute(result) });
+            break;
+        }
+    }
+    println!("");
+
+    if let Some(res) = out {
+        let ctx = instance.context();
+        let memory = ctx.memory(0);
+        let wasm_ptr: WasmPtr<u8, Array> = WasmPtr::new(res.ptr);
+
+        let password_str = wasm_ptr.get_utf8_string(memory, res.len).unwrap();
+
+        let end_ts = time::SteadyTime::now();
+        let delta = end_ts - start_ts;
+        println!(
+            "Password cracked: \"{}\" in {}.{:03}",
+            password_str,
+            delta.num_seconds(),
+            (delta.num_milliseconds() % 1000),
+        );
+    } else {
+        println!("Password not found!");
+    }
+}