jcs.org
qemu with hax to log dma reads & writes
jcs.org/2018/11/12/vfio
tests/plugin: add hotpages to analyse memory access patterns
This plugin gives a summary of access patterns grouped by "pages" and
showing read/write patterns by vCPUS.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
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tests/plugin/Makefile
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tests/plugin/Makefile
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tests/plugin/hotpages.c
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tests/plugin/hotpages.c
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/*
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* Copyright (C) 2019, Alex Bennée <alex.bennee@linaro.org>
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*
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* Hot Pages - show which pages saw the most memory accesses.
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*
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* License: GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#include <inttypes.h>
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#include <assert.h>
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#include <stdlib.h>
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#include <inttypes.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <glib.h>
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#include <qemu-plugin.h>
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#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
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static uint64_t page_size = 4096;
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static uint64_t page_mask;
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static int limit = 50;
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static enum qemu_plugin_mem_rw rw = QEMU_PLUGIN_MEM_RW;
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static bool track_io;
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enum sort_type {
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SORT_RW = 0,
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SORT_R,
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SORT_W,
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SORT_A
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};
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static int sort_by = SORT_RW;
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typedef struct {
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uint64_t page_address;
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int cpu_read;
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int cpu_write;
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uint64_t reads;
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uint64_t writes;
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} PageCounters;
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static GMutex lock;
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static GHashTable *pages;
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static gint cmp_access_count(gconstpointer a, gconstpointer b)
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{
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PageCounters *ea = (PageCounters *) a;
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PageCounters *eb = (PageCounters *) b;
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int r;
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switch (sort_by) {
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case SORT_RW:
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r = (ea->reads + ea->writes) > (eb->reads + eb->writes) ? -1 : 1;
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break;
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case SORT_R:
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r = ea->reads > eb->reads ? -1 : 1;
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break;
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case SORT_W:
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r = ea->writes > eb->writes ? -1 : 1;
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break;
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case SORT_A:
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r = ea->page_address > eb->page_address ? -1 : 1;
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break;
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default:
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g_assert_not_reached();
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}
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return r;
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}
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static void plugin_exit(qemu_plugin_id_t id, void *p)
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{
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g_autoptr(GString) report = g_string_new("Addr, RCPUs, Reads, WCPUs, Writes\n");
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int i;
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GList *counts;
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counts = g_hash_table_get_values(pages);
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if (counts && g_list_next(counts)) {
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GList *it;
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it = g_list_sort(counts, cmp_access_count);
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for (i = 0; i < limit && it->next; i++, it = it->next) {
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PageCounters *rec = (PageCounters *) it->data;
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g_string_append_printf(report,
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"%#016"PRIx64", 0x%04x, %"PRId64
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", 0x%04x, %"PRId64"\n",
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rec->page_address,
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rec->cpu_read, rec->reads,
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rec->cpu_write, rec->writes);
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}
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g_list_free(it);
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}
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qemu_plugin_outs(report->str);
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}
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static void plugin_init(void)
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{
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page_mask = (page_size - 1);
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pages = g_hash_table_new(NULL, g_direct_equal);
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}
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static void vcpu_haddr(unsigned int cpu_index, qemu_plugin_meminfo_t meminfo,
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uint64_t vaddr, void *udata)
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{
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struct qemu_plugin_hwaddr *hwaddr = qemu_plugin_get_hwaddr(meminfo, vaddr);
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uint64_t page;
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PageCounters *count;
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/* We only get a hwaddr for system emulation */
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if (track_io) {
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if (hwaddr && qemu_plugin_hwaddr_is_io(hwaddr)) {
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page = vaddr;
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} else {
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return;
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}
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} else {
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if (hwaddr && !qemu_plugin_hwaddr_is_io(hwaddr)) {
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page = (uint64_t) qemu_plugin_hwaddr_device_offset(hwaddr);
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} else {
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page = vaddr;
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}
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}
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page &= ~page_mask;
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g_mutex_lock(&lock);
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count = (PageCounters *) g_hash_table_lookup(pages, GUINT_TO_POINTER(page));
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if (!count) {
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count = g_new0(PageCounters, 1);
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count->page_address = page;
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g_hash_table_insert(pages, GUINT_TO_POINTER(page), (gpointer) count);
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}
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if (qemu_plugin_mem_is_store(meminfo)) {
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count->writes++;
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count->cpu_write |= (1 << cpu_index);
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} else {
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count->reads++;
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count->cpu_read |= (1 << cpu_index);
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}
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g_mutex_unlock(&lock);
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}
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static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
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{
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size_t n = qemu_plugin_tb_n_insns(tb);
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size_t i;
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for (i = 0; i < n; i++) {
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struct qemu_plugin_insn *insn = qemu_plugin_tb_get_insn(tb, i);
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qemu_plugin_register_vcpu_mem_cb(insn, vcpu_haddr,
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QEMU_PLUGIN_CB_NO_REGS,
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rw, NULL);
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}
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}
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QEMU_PLUGIN_EXPORT
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int qemu_plugin_install(qemu_plugin_id_t id, const qemu_info_t *info,
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int argc, char **argv)
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{
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int i;
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for (i = 0; i < argc; i++) {
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char *opt = argv[i];
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if (g_strcmp0(opt, "reads") == 0) {
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sort_by = SORT_R;
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} else if (g_strcmp0(opt, "writes") == 0) {
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sort_by = SORT_W;
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} else if (g_strcmp0(opt, "address") == 0) {
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sort_by = SORT_A;
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} else if (g_strcmp0(opt, "io") == 0) {
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track_io = true;
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} else if (g_str_has_prefix(opt, "pagesize=")) {
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page_size = g_ascii_strtoull(opt + 9, NULL, 10);
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} else {
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fprintf(stderr, "option parsing failed: %s\n", opt);
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return -1;
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}
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}
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plugin_init();
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qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans);
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qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
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return 0;
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}