From da718c9fb4f7e29a89161b0814b7b183771ad4f1 Mon Sep 17 00:00:00 2001
From: tomsmeding <tom.smeding@gmail.com>
Date: Sat, 20 Apr 2019 14:39:39 +0200
Subject: Chunked computations

---
 aberth/aberth.cpp        | 124 ++++++++++++++++++++++++++++++++++++-----------
 aberth/aberth_kernel.fut |   4 +-
 2 files changed, 98 insertions(+), 30 deletions(-)

diff --git a/aberth/aberth.cpp b/aberth/aberth.cpp
index 30f40f6..c5b037d 100644
--- a/aberth/aberth.cpp
+++ b/aberth/aberth.cpp
@@ -11,6 +11,7 @@
 #include <algorithm>
 #include <thread>
 #include <mutex>
+#include <type_traits>
 #include <cstdint>
 #include <cassert>
 #include "../lodepng.h"
@@ -346,18 +347,11 @@ static vector<uint8_t> drawImage(int W, int H, const vector<int> &counts, int ma
 	return image;
 }
 
-static vector<int32_t> invoke_kernel(
-		int32_t width, int32_t height,
-		Com bottomLeft, Com topRight,
-		int32_t seed) {
+class Kernel {
+	futhark_context *ctx;
+	int32_t N;
 
-	futhark_context_config *config = futhark_context_config_new();
-	// futhark_context_config_select_device_interactively(config);
-	// futhark_context_config_set_debugging(config, 1);
-
-	futhark_context *ctx = futhark_context_new(config);
-
-	auto check_ret = [ctx](int ret) {
+	void check_ret(int ret) {
 		if (ret != 0) {
 			char *str = futhark_context_get_error(ctx);
 			cerr << str << endl;
@@ -366,29 +360,101 @@ static vector<int32_t> invoke_kernel(
 		}
 	};
 
-	futhark_i32_1d *dest_arr;
+public:
+	static_assert(is_same<int32_t, int>::value);
 
-	check_ret(futhark_entry_main_all(
-			ctx, &dest_arr,
-			width, height,
-			bottomLeft.real(), topRight.imag(),
-			topRight.real(), bottomLeft.imag(),
-			seed));
+	Kernel() {
+		futhark_context_config *config = futhark_context_config_new();
+		// futhark_context_config_select_device_interactively(config);
+		// futhark_context_config_set_debugging(config, 1);
 
-	check_ret(futhark_context_sync(ctx));
+		ctx = futhark_context_new(config);
 
-	// Shouldn't free _this_ pointer, apparently
-	int64_t *shape = futhark_shape_i32_1d(ctx, dest_arr);
-	assert(shape[0] == width * height);
+		futhark_context_config_free(config);
 
-	vector<int32_t> buffer(width * height);
-	check_ret(futhark_values_i32_1d(ctx, dest_arr, buffer.data()));
-	check_ret(futhark_free_i32_1d(ctx, dest_arr));
+		check_ret(futhark_entry_get_N(ctx, &N));
+		// The 31 check is to not exceed 32-bit signed integer bounds
+		assert(N >= 1 && N < 31);
+	}
 
-	futhark_context_config_free(config);
+	~Kernel() {
+		futhark_context_free(ctx);
+	}
 
-	return buffer;
-}
+	void run_job(
+			vector<int32_t> &dest,
+			int32_t width, int32_t height,
+			Com bottomLeft, Com topRight,
+			int32_t seed,
+			int32_t start_index, int32_t poly_count) {
+
+		futhark_i32_1d *dest_arr;
+
+		check_ret(futhark_entry_main_job(
+				ctx, &dest_arr,
+				start_index, poly_count,
+				width, height,
+				bottomLeft.real(), topRight.imag(),
+				topRight.real(), bottomLeft.imag(),
+				seed));
+
+		check_ret(futhark_context_sync(ctx));
+
+		int64_t shape = futhark_shape_i32_1d(ctx, dest_arr)[0];
+		assert(shape == width * height);
+
+		dest.resize(width * height);
+		check_ret(futhark_values_i32_1d(ctx, dest_arr, dest.data()));
+		check_ret(futhark_free_i32_1d(ctx, dest_arr));
+	}
+
+	void run_all(
+			vector<int32_t> &dest,
+			int32_t width, int32_t height,
+			Com bottomLeft, Com topRight,
+			int32_t seed) {
+
+		run_job(dest, width, height, bottomLeft, topRight, seed, 0, 1 << N);
+	}
+
+	void run_chunked(
+			vector<int32_t> &dest,
+			int32_t width, int32_t height,
+			Com bottomLeft, Com topRight,
+			int32_t seed,
+			int32_t chunk_size) {
+
+		dest.clear();
+		dest.resize(width * height);
+
+		int32_t start_index = 0;
+		int32_t total = 1 << N;
+
+		int32_t njobs = (total + chunk_size - 1) / chunk_size;
+		cerr << "Running " << njobs << " jobs of size " << chunk_size << endl;
+		cerr << string(njobs, '.') << '\r';
+
+		while (start_index < total) {
+			int32_t num_polys = min(chunk_size, total - start_index);
+
+			vector<int32_t> output;
+			run_job(
+				output,
+				width, height, bottomLeft, topRight, seed,
+				start_index, num_polys);
+
+			for (int i = 0; i < width * height; i++) {
+				dest[i] += output[i];
+			}
+
+			start_index += num_polys;
+
+			cerr << '|';
+		}
+
+		cerr << endl;
+	}
+};
 
 int main(int argc, char **argv) {
 	int W, H;
@@ -399,7 +465,7 @@ int main(int argc, char **argv) {
 		W = H = 2000;
 		Com bottomLeft = Com(0, -1.6);
 		Com topRight = Com(1.6, 0);
-		counts = invoke_kernel(W, H, bottomLeft, topRight, 42);
+		Kernel().run_chunked(counts, W, H, bottomLeft, topRight, 42, 1 << 14);
 		writeCounts(W, H, counts, "out.txt");
 	} else if (argc == 2) {
 		tie(W, H, counts) = readCounts(argv[1]);
diff --git a/aberth/aberth_kernel.fut b/aberth/aberth_kernel.fut
index be1fed0..e1e7aa3 100644
--- a/aberth/aberth_kernel.fut
+++ b/aberth/aberth_kernel.fut
@@ -7,7 +7,7 @@ module uniform_real = uniform_real_distribution f32 rand_engine
 module cplx = mk_complex f32
 type complex = cplx.complex
 
-let N = 18i32
+let N = 22i32
 let PolyN = N + 1
 
 type poly = [PolyN]f32
@@ -167,3 +167,5 @@ entry main_all
         (seed: i32)
         : []i32 =
     main_job 0 (1 << N) width height left top right bottom seed
+
+entry get_N: i32 = N
-- 
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