wasmtime / issue #6159 Cranelift and suboptimal instructi... · git-wasmtime

I did a bit of work recently to get a build of XNNPACK working with Wasmtime. My original motivation for doing this was that XNNPACK has been used as a benchmark to evaluate a number of changes to the simd proposal to WebAssembly (and relaxed-simd), so it seemed like a great candidate to test as baselines between WebAssembly engines and native performance. The master branch of that repository itself doesn't support WASI as a target, so I hacked up a bunch of commits and updated the intrinsics to the LLVM 16 versions. Using that I was able to produce a WebAssembly file with:

./bazelisk-linux-arm64 build -c opt --config wasi --features wasm_relaxed_simd :end2end_bench

I'll be honest in that there's a ton of benchmarks listed in the BUILD.bazel file for that repository and I don't know if "end2end" is the "main" one or if there even is a "main" one. Nevertheless it sounded right and I figured it was at least one good starting point.

set -e
wasmtime="../wasmtime/target/release/wasmtime run --disable-cache \
  --wasm-features threads,relaxed-simd \
  --wasi-modules experimental-wasi-threads \
  --"
wasmtime2="../wasmtime/target/release/wasmtime run --disable-cache \
  --wasm-features threads,relaxed-simd \
  --wasi-modules experimental-wasi-threads \
  --cranelift-set use_egraphs=false \
  --"
node="node \
  --experimental-wasm-relaxed-simd \
  --experimental-wasi-unstable-preview1 \
  ../meshoptimizer/run.mjs"
spidermonkey="../gecko-dev/obj-opt-aarch64-unknown-linux-gnu/dist/bin/js \
  ../wasmtime/spidermonkey.js"
v8="../v8/out/arm64.release/d8 \
  --experimental-wasm-relaxed-simd \
  ../wasmtime/v8.js --"

for t in `$wasmtime ./end2end.simd.relaxed.wasm --benchmark_list_tests | rg -v FP16`; do
  # echo ====================================================================

  for file in end2end.simd.relaxed.wasm; do
    # echo == $file ==
    echo -n "wasmtime     "
    $wasmtime ./$file --benchmark_filter=$t 2>&1 | rg $t
    echo -n "wasmtime2    "
    $wasmtime2 ./$file --benchmark_filter=$t 2>&1 | rg $t
    echo -n "node         "
    $node ./$file --benchmark_filter=$t 2>&1 | rg $t
    echo -n "spidermonkey "
    $spidermonkey ./$file --benchmark_filter=$t 2>&1 | rg $t
    echo -n "v8           "
    $v8 ./$file --benchmark_filter=$t 2>&1 | rg $t
    echo -n "native       "
    ./end2end_bench --benchmark_filter=$t 2>&1 | rg $t

  done
  echo

done

import { readFile } from 'node:fs/promises';
import { WASI } from 'wasi';
import { argv } from 'node:process';

const wasi = new WASI({
  version: 'preview1',
  args: argv.slice(2),
});

const m = process.argv[2];
const wasm = await WebAssembly.compile(await readFile(m));
const obj = wasi.getImportObject();
obj.env = {
  memory: new WebAssembly.Memory({shared: true, initial: 8000, maximum: 16000}),
};
obj.wasi = {
  'thread-spawn': function() {
    throw new Error('wasi thread spawn');
  },
};
const instance = await WebAssembly.instantiate(wasm, obj);
wasi.start(instance);

const ITERS = 1;

////////////////////////////////////////////////////////////////////////////////

class TextEncoder {
  constructor(enc) {
    if (enc != "utf-8") {
      throw new Error("FITZGEN: unsupported encoding: " + enc);
    }
  }
  encode(s, n) {
    let buf = new Uint8Array(s.length);
    for (let i = 0; i < Math.min(s.length, n); i++) {
      buf[i] = s.charCodeAt(i); // lol
    }
    return buf;
  }
};

class TextDecoder {
  constructor(enc) {
    if (enc != "utf-8") {
      throw new Error("FITZGEN: unsupported encoding: " + enc);
    }
  }
  decode(buf) {
    let buf8 = new Uint8Array(buf);
    let s = "";
    for (let i = 0; i < buf8.length; i++) {
      s += String.fromCharCode(buf8[i]); // lol
    }
    return s;
  }
};

////////////////////////////////////////////////////////////////////////////////

async function ionCompile(wasm) {
  let module = await WebAssembly.compile(wasm);
  while (!wasmHasTier2CompilationCompleted(module)) {
    sleep(1);
  }
  // wasmDis(module);
  return module;
}

function unimplemented(name) {
  return function (...args) {
    throw new Error(name + " is unimplemented! args = " + args);
  }
}

class ProcExitError extends Error {
  constructor(code) {
    this.code = code;
    this.message = "Program exited with code " + code;
  }
  toString() {
    return "ProcExitError: " + this.message
  }
}

function trace(obj) {
  let proxy = {};
  for (let key of Object.keys(obj)) {
    if (typeof obj[key] != "function") {
      proxy[key] = obj[key];
      continue;
    }
    proxy[key] = function (...args) {
      print("TRACE: " + key + "(" + args + ")");
      let ret = obj[key](...args);
      print("TRACE:   -> " + ret);
      return ret;
    };
  }
  return proxy;
}

////////////////////////////////////////////////////////////////////////////////

async function main() {
  let smWasm = os.file.readFile(scriptArgs[0], "binary");
  let smModule = await ionCompile(smWasm);

  for (let i = 0; i < ITERS; i++) {
    let args = scriptArgs;
    let mem = null;
    let start = null;
    let unread = true;

    let smInstance = await WebAssembly.instantiate(smModule, trace({
      env: {
        memory: new WebAssembly.Memory({
          shared: true,
          minimum: 8000,
          maximum: 16000,
        }),
      },
      bench: {
        start: function () {
          start = monotonicNow()
        },
        end: function () {
          let end = monotonicNow();
          print("ITER: " + (end - start));
        }
      },
      wasi: {
        'thread-spawn': function() {
          throw new Error('thread-spawn');
        },
      },
      wasi_snapshot_preview1: {
        fd_pread: function() { throw new Error('fd_pread'); },
        poll_oneoff: function(in_, out, n) {
          console.log(n);
          // throw new Error('poll_oneoff');
          return 0;
        },
        random_get: function(a, b) {
          while (b > 0) {
            (new DataView(mem.buffer)).setInt8(a, 1, true);
            b -= 1;
            a += 1;
          }
          return 0;
        },
        args_get: function(a, b) {
          for (let arg of args) {
            (new DataView(mem.buffer)).setInt32(a, b, true);
            a += 4;
            for (let c in arg) {
              (new DataView(mem.buffer)).setInt8(b, arg.charCodeAt(c), true);
              b += 1;
            }
            (new DataView(mem.buffer)).setInt8(b, 0, true);
            b += 1;
          }
          return 0;
        },
        args_sizes_get: function(a, b) {
          let len = 0;
          for (let arg of args) {
            len += arg.length + 1;
          }
          (new DataView(mem.buffer)).setInt32(a, args.length, true);
          (new DataView(mem.buffer)).setInt32(b, len, true);
          return 0;
        },
        clock_res_get: function () { return 1; },
        clock_time_get: function(a, b, c) {
          const now = Math.round(performance.now() * 1000000);
          (new DataView(mem.buffer)).setBigInt64(c, BigInt(now), true);
          return 0;
        },
        fd_filestat_get: function() { throw new Error('fd_filestat_get'); },
        fd_read: function(fd, iovecs_ptr, iovecs_len, out_ptr) {
          let mem8 = new Uint8Array(mem.buffer);
          switch (fd) {
          case 4:
            let data = os.file.readFile("/home/nick/sightglass/benchmarks/spidermonkey/default.input.md");
            let k = 0;
            for (let i = 0; i < iovecs_len && k < data.length && unread; i++) {
              let ptr = (new DataView(mem.buffer)).getUint32(iovecs_ptr + i * 8, true);
              let len = (new DataView(mem.buffer)).getUint32(iovecs_ptr + i * 8 + 4, true);
              for (let j = 0; j < len && k < data.length; j++) {
                mem8[ptr + j] = data.charCodeAt(k++);
              }
            }
            unread = false;
            (new DataView(mem.buffer)).setUint32(out_ptr, k, true);
            return 0;
          default:
            return 8;
          }
        },
        fd_seek: function(fd, offset, whence, out_ptr) {
          switch (fd) {
          case 4:
            let len = os.file.readFile("/home/nick/sightglass/benchmarks/spidermonkey/default.input.md").length;
            (new DataView(mem.buffer)).setBigUint64(out_ptr, BigInt(len), true);
            return 0;
          default:
            return 8;
          }
        },
        fd_write: function(a, b, c, d) {
          let s = '';
          let total = 0;
          while (c > 0) {
            let base = (new DataView(mem.buffer)).getInt32(b, true);
            let len = (new DataView(mem.buffer)).getInt32(b + 4, true);
            b += 8;
            c -= 1;

            while (len > 0) {
              let c = new Uint8Array(mem.buffer)[base]
              s += String.fromCharCode(c);
              len -= 1;
              base += 1;
              total += 1;
            }
          }
          //print("fd_write(" + a + "): " + s.trimEnd());
          print(s.trimEnd());
          (new DataView(mem.buffer)).setInt32(d, total, true);
          return 0;
        },
        fd_fdstat_
[message truncated]

Stream: git-wasmtime

Topic: wasmtime / issue #6159 Cranelift and suboptimal instructi...

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