diff options
| -rw-r--r-- | contrib/plugins/Makefile | 1 | ||||
| -rw-r--r-- | contrib/plugins/hwprofile.c | 305 | ||||
| -rw-r--r-- | docs/devel/tcg-plugins.rst | 34 |
3 files changed, 340 insertions, 0 deletions
diff --git a/contrib/plugins/Makefile b/contrib/plugins/Makefile index 7801b08..b9d7935 100644 --- a/contrib/plugins/Makefile +++ b/contrib/plugins/Makefile @@ -17,6 +17,7 @@ NAMES += hotblocks NAMES += hotpages NAMES += howvec NAMES += lockstep +NAMES += hwprofile SONAMES := $(addsuffix .so,$(addprefix lib,$(NAMES))) diff --git a/contrib/plugins/hwprofile.c b/contrib/plugins/hwprofile.c new file mode 100644 index 0000000..6dac1d5 --- /dev/null +++ b/contrib/plugins/hwprofile.c @@ -0,0 +1,305 @@ +/* + * 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; +} diff --git a/docs/devel/tcg-plugins.rst b/docs/devel/tcg-plugins.rst index 0568dfa..39ce86e 100644 --- a/docs/devel/tcg-plugins.rst +++ b/docs/devel/tcg-plugins.rst @@ -280,3 +280,37 @@ which will eventually report:: previously @ 0x000000ffd08098/5 (809900593 insns) previously @ 0x000000ffd080c0/1 (809900588 insns) +- contrib/plugins/hwprofile + +The hwprofile tool can only be used with system emulation and allows +the user to see what hardware is accessed how often. It has a number of options: + + * arg=read or arg=write + + By default the plugin tracks both reads and writes. You can use one + of these options to limit the tracking to just one class of accesses. + + * arg=source + + Will include a detailed break down of what the guest PC that made the + access was. Not compatible with arg=pattern. Example output:: + + cirrus-low-memory @ 0xfffffd00000a0000 + pc:fffffc0000005cdc, 1, 256 + pc:fffffc0000005ce8, 1, 256 + pc:fffffc0000005cec, 1, 256 + + * arg=pattern + + Instead break down the accesses based on the offset into the HW + region. This can be useful for seeing the most used registers of a + device. Example output:: + + pci0-conf @ 0xfffffd01fe000000 + off:00000004, 1, 1 + off:00000010, 1, 3 + off:00000014, 1, 3 + off:00000018, 1, 2 + off:0000001c, 1, 2 + off:00000020, 1, 2 + ... |