qemu/contrib/plugins/hwprofile.c

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/*
* Copyright (C) 2020, Alex Bennée <alex.bennee@linaro.org>
*
* HW Profile - breakdown access patterns for IO to devices
*
* License: GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include <inttypes.h>
#include <assert.h>
#include <stdlib.h>
#include <inttypes.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <glib.h>
#include <qemu-plugin.h>
QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION;
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
typedef struct {
uint64_t cpu_read;
uint64_t cpu_write;
uint64_t reads;
uint64_t writes;
} IOCounts;
typedef struct {
uint64_t off_or_pc;
IOCounts counts;
} IOLocationCounts;
typedef struct {
const char *name;
uint64_t base;
IOCounts totals;
GHashTable *detail;
} DeviceCounts;
static GMutex lock;
static GHashTable *devices;
/* track the access pattern to a piece of HW */
static bool pattern;
/* track the source address of access to HW */
static bool source;
/* track only matched regions of HW */
static bool check_match;
static gchar **matches;
static enum qemu_plugin_mem_rw rw = QEMU_PLUGIN_MEM_RW;
static inline bool track_reads(void)
{
return rw == QEMU_PLUGIN_MEM_RW || rw == QEMU_PLUGIN_MEM_R;
}
static inline bool track_writes(void)
{
return rw == QEMU_PLUGIN_MEM_RW || rw == QEMU_PLUGIN_MEM_W;
}
static void plugin_init(void)
{
devices = g_hash_table_new(NULL, NULL);
}
static gint sort_cmp(gconstpointer a, gconstpointer b)
{
DeviceCounts *ea = (DeviceCounts *) a;
DeviceCounts *eb = (DeviceCounts *) b;
return ea->totals.reads + ea->totals.writes >
eb->totals.reads + eb->totals.writes ? -1 : 1;
}
static gint sort_loc(gconstpointer a, gconstpointer b)
{
IOLocationCounts *ea = (IOLocationCounts *) a;
IOLocationCounts *eb = (IOLocationCounts *) b;
return ea->off_or_pc > eb->off_or_pc;
}
static void fmt_iocount_record(GString *s, IOCounts *rec)
{
if (track_reads()) {
g_string_append_printf(s, ", %"PRIx64", %"PRId64,
rec->cpu_read, rec->reads);
}
if (track_writes()) {
g_string_append_printf(s, ", %"PRIx64", %"PRId64,
rec->cpu_write, rec->writes);
}
}
static void fmt_dev_record(GString *s, DeviceCounts *rec)
{
g_string_append_printf(s, "%s, 0x%"PRIx64,
rec->name, rec->base);
fmt_iocount_record(s, &rec->totals);
g_string_append_c(s, '\n');
}
static void plugin_exit(qemu_plugin_id_t id, void *p)
{
g_autoptr(GString) report = g_string_new("");
GList *counts;
if (!(pattern || source)) {
g_string_printf(report, "Device, Address");
if (track_reads()) {
g_string_append_printf(report, ", RCPUs, Reads");
}
if (track_writes()) {
g_string_append_printf(report, ", WCPUs, Writes");
}
g_string_append_c(report, '\n');
}
counts = g_hash_table_get_values(devices);
if (counts && g_list_next(counts)) {
GList *it;
it = g_list_sort(counts, sort_cmp);
while (it) {
DeviceCounts *rec = (DeviceCounts *) it->data;
if (rec->detail) {
GList *accesses = g_hash_table_get_values(rec->detail);
GList *io_it = g_list_sort(accesses, sort_loc);
const char *prefix = pattern ? "off" : "pc";
g_string_append_printf(report, "%s @ 0x%"PRIx64"\n",
rec->name, rec->base);
while (io_it) {
IOLocationCounts *loc = (IOLocationCounts *) io_it->data;
g_string_append_printf(report, " %s:%08"PRIx64,
prefix, loc->off_or_pc);
fmt_iocount_record(report, &loc->counts);
g_string_append_c(report, '\n');
io_it = io_it->next;
}
} else {
fmt_dev_record(report, rec);
}
it = it->next;
};
g_list_free(it);
}
qemu_plugin_outs(report->str);
}
static DeviceCounts *new_count(const char *name, uint64_t base)
{
DeviceCounts *count = g_new0(DeviceCounts, 1);
count->name = name;
count->base = base;
if (pattern || source) {
count->detail = g_hash_table_new(NULL, NULL);
}
g_hash_table_insert(devices, (gpointer) name, count);
return count;
}
static IOLocationCounts *new_location(GHashTable *table, uint64_t off_or_pc)
{
IOLocationCounts *loc = g_new0(IOLocationCounts, 1);
loc->off_or_pc = off_or_pc;
g_hash_table_insert(table, (gpointer) off_or_pc, loc);
return loc;
}
static void hwprofile_match_hit(DeviceCounts *rec, uint64_t off)
{
g_autoptr(GString) report = g_string_new("hwprofile: match @ offset");
g_string_append_printf(report, "%"PRIx64", previous hits\n", off);
fmt_dev_record(report, rec);
qemu_plugin_outs(report->str);
}
static void inc_count(IOCounts *count, bool is_write, unsigned int cpu_index)
{
if (is_write) {
count->writes++;
count->cpu_write |= (1 << cpu_index);
} else {
count->reads++;
count->cpu_read |= (1 << cpu_index);
}
}
static void vcpu_haddr(unsigned int cpu_index, qemu_plugin_meminfo_t meminfo,
uint64_t vaddr, void *udata)
{
struct qemu_plugin_hwaddr *hwaddr = qemu_plugin_get_hwaddr(meminfo, vaddr);
if (!hwaddr || !qemu_plugin_hwaddr_is_io(hwaddr)) {
return;
} else {
const char *name = qemu_plugin_hwaddr_device_name(hwaddr);
uint64_t off = qemu_plugin_hwaddr_device_offset(hwaddr);
bool is_write = qemu_plugin_mem_is_store(meminfo);
DeviceCounts *counts;
g_mutex_lock(&lock);
counts = (DeviceCounts *) g_hash_table_lookup(devices, name);
if (!counts) {
uint64_t base = vaddr - off;
counts = new_count(name, base);
}
if (check_match) {
if (g_strv_contains((const char * const *)matches, counts->name)) {
hwprofile_match_hit(counts, off);
inc_count(&counts->totals, is_write, cpu_index);
}
} else {
inc_count(&counts->totals, is_write, cpu_index);
}
/* either track offsets or source of access */
if (source) {
off = (uint64_t) udata;
}
if (pattern || source) {
IOLocationCounts *io_count = g_hash_table_lookup(counts->detail,
(gpointer) off);
if (!io_count) {
io_count = new_location(counts->detail, off);
}
inc_count(&io_count->counts, is_write, cpu_index);
}
g_mutex_unlock(&lock);
}
}
static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
{
size_t n = qemu_plugin_tb_n_insns(tb);
size_t i;
for (i = 0; i < n; i++) {
struct qemu_plugin_insn *insn = qemu_plugin_tb_get_insn(tb, i);
gpointer udata = (gpointer) (source ? qemu_plugin_insn_vaddr(insn) : 0);
qemu_plugin_register_vcpu_mem_cb(insn, vcpu_haddr,
QEMU_PLUGIN_CB_NO_REGS,
rw, udata);
}
}
QEMU_PLUGIN_EXPORT
int qemu_plugin_install(qemu_plugin_id_t id, const qemu_info_t *info,
int argc, char **argv)
{
int i;
for (i = 0; i < argc; i++) {
char *opt = argv[i];
if (g_strcmp0(opt, "read") == 0) {
rw = QEMU_PLUGIN_MEM_R;
} else if (g_strcmp0(opt, "write") == 0) {
rw = QEMU_PLUGIN_MEM_W;
} else if (g_strcmp0(opt, "pattern") == 0) {
pattern = true;
} else if (g_strcmp0(opt, "source") == 0) {
source = true;
} else if (g_str_has_prefix(opt, "match")) {
gchar **parts = g_strsplit(opt, "=", 2);
check_match = true;
matches = g_strsplit(parts[1], ",", -1);
g_strfreev(parts);
} else {
fprintf(stderr, "option parsing failed: %s\n", opt);
return -1;
}
}
if (source && pattern) {
fprintf(stderr, "can only currently track either source or pattern.\n");
return -1;
}
if (!info->system_emulation) {
fprintf(stderr, "hwprofile: plugin only useful for system emulation\n");
return -1;
}
/* Just warn about overflow */
if (info->system.smp_vcpus > 64 ||
info->system.max_vcpus > 64) {
fprintf(stderr, "hwprofile: can only track up to 64 CPUs\n");
}
plugin_init();
qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans);
qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
return 0;
}