/* 
 * Copyright 2014 Steffen Vogel, Chair for Operating Systems,
 *                               RWTH Aachen University
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * This file is part of MetalSVM.
 */
/**
 * @author Steffen Vogel <steffen.vogel@rwth-aachen.de>
 *
 *  Based on:
 *   www.cs.berkeley.edu/~richie/bebop/notes/matmul/files/membench/
 */

#include <metalsvm/stdio.h>
#include <metalsvm/vma.h>
#include <metalsvm/malloc.h>

#include <asm/processor.h>
#include <asm/pmc.h>

#define SAMPLES		1000
#define CLKS		1000000000L

#define STRIDE_MIN	1

#define RANGE_MIN	(32)		/* 32 Byte */
#define RANGE_MAX	(32*1024*1024)	/* 32 MiB */

#define FLUSH		1

static inline void warmup(char* memory)
{
#ifdef FLUSH
	tlb_flush();
	flush_cache();
#else
	int index;
	for (index = 0; index < RANGE_MAX; index++) {
		memory[index] = 0;
	}
#endif
}

int membench(void* arg)
{
	kprintf("======= Starting membench\n");

	/* Init PMCs */
	struct pmc_caps* cap = pmc_init();

	kprintf("PMC architecural version: %u\n", cap->version);
	kprintf("There are %u general purpose PMCs (%u bit wide) available\n", cap->gp_count, cap->gp_width);
	kprintf("There are %u fixed function PMCs (%u bit wide) available\n", cap->ff_count, cap->ff_width);

	int i;

	uint16_t tests[][2] = {
#if 0
		{PMC_EVT_MEM_LOAD_RETIRED_DTLB_MISS, 0}
		{PMC_EVT_MEM_LOAD_RETIRED_L1D_MISS, 0}
		{PMC_EVT_MEM_LOAD_RETIRED_L2_MISS, 0}
#elif 0
		{PMC_EVT_PAGE_WALK_CLKS, PMC_EVT_PAGE_WALK_COUNT}
#else
		{PMC_EVT_DTLB_MISS_ANY, PMC_EVT_DTLB_MISS_LD},
		{PMC_EVT_DTLB_MISS_ANY, PMC_EVT_DTLB_MISS_L0_LD},
		{PMC_EVT_DTLB_MISS_ANY, PMC_EVT_DTLB_MISS_ST},
#endif
	};


	char *memory = palloc(RANGE_MAX, 0);
	kprintf("Allocated test memory: %#lx bytes at %p\n", RANGE_MAX, memory);

	kprintf("#%12s%12s%12s%12s%12s%12s\n", "range", "stride", "steps", "runs", "reads", "results");

	irq_disable();

	/* Setup PMCs */
	pmc_stop_all();
	pmc_ff_config(1, PMC_FIXED_OS); // CPU_CLK_UNHALTED.CORE

	/* Variables for PMC values */
	uint64_t gp[2], ff[3];
	uint64_t gp_ovh[2], ff_ovh[3];
	int64_t gp_real[2], ff_real[3];
	uint64_t run, steps, tsteps, index, runs, reads;
	uint64_t range, stride;
	volatile char temp;

	/* Run the timing experiments */
	for (range = RANGE_MIN; range <= RANGE_MAX; range *= 2) {
		for (stride = STRIDE_MIN; stride < range; stride *= 2) {
			runs = SAMPLES * stride / range + 1;

			for (i = 0; i < sizeof(tests) / 4; i++) {
				pmc_gp_config(0, tests[i][0], PMC_EVTSEL_OS | PMC_EVTSEL_EN, 0, 0);
				pmc_gp_config(1, tests[i][1], PMC_EVTSEL_OS | PMC_EVTSEL_EN, 0, 0);

				steps = 0;
				tsteps = 0;

				/* Time the loop with strided access + loop overhead */
				warmup(memory);
				pmc_reset_all();
				pmc_start_all();
				do {
					for (run = 0; run < runs; run++) {
						for (index = 0; index < range; index += stride) {
							temp = memory[index];
						}
					}

					steps++;
				} while (pmc_ff_read(1) < CLKS);

				pmc_stop_all();

				gp[0] = pmc_gp_read(0);
				gp[1] = pmc_gp_read(1);
				ff[1] = pmc_ff_read(1);

				/* Try to time just the overheads */
				warmup(memory);
				pmc_reset_all();
				pmc_start_all();
				do {
					for (run = 0; run < runs; run++) {
						for (index = 0; index < range; index += stride) {
							temp++;
						}
					}

					tsteps++;
				} while (tsteps < steps);
				pmc_stop_all();

				gp_ovh[0] = pmc_gp_read(0);
				gp_ovh[1] = pmc_gp_read(1);
				ff_ovh[1] = pmc_ff_read(1);

				gp_real[0] = gp[0] - gp_ovh[0];
				gp_real[1] = gp[1] - gp_ovh[1];
				ff_real[1] = ff[1] - ff_ovh[1];

				reads = runs * steps * range / stride;

				if (i == 0)
					kprintf("%12llu%12llu%12llu%12llu%12llu%12llu", range, stride, steps, runs, reads, ff_real[1]);

				kprintf("%12llu", gp_real[0]);
				kprintf("%12llu", gp_real[1]);
				kprintf("\t");
			}
			kprintf("\n");
		}
		kprintf("\n");
	}

	irq_enable();

	return 0;
}