diff --git a/tests/plugin/howvec.c b/tests/plugin/howvec.c
new file mode 100644
index 0000000..58fa675
--- /dev/null
+++ b/tests/plugin/howvec.c
@@ -0,0 +1,352 @@
+/*
+ * Copyright (C) 2019, Alex Bennée <alex.bennee@linaro.org>
+ *
+ * How vectorised is this code?
+ *
+ * Attempt to measure the amount of vectorisation that has been done
+ * on some code by counting classes of instruction.
+ *
+ * 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>
+
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+
+typedef enum {
+    COUNT_CLASS,
+    COUNT_INDIVIDUAL,
+    COUNT_NONE
+} CountType;
+
+static int limit = 50;
+static bool do_inline;
+static bool verbose;
+
+static GMutex lock;
+static GHashTable *insns;
+
+typedef struct {
+    const char *class;
+    const char *opt;
+    uint32_t mask;
+    uint32_t pattern;
+    CountType what;
+    uint64_t count;
+} InsnClassExecCount;
+
+typedef struct {
+    char *insn;
+    uint32_t opcode;
+    uint64_t count;
+    InsnClassExecCount *class;
+} InsnExecCount;
+
+/*
+ * Matchers for classes of instructions, order is important.
+ *
+ * Your most precise match must be before looser matches. If no match
+ * is found in the table we can create an individual entry.
+ *
+ * 31..28 27..24 23..20 19..16 15..12 11..8 7..4 3..0
+ */
+static InsnClassExecCount aarch64_insn_classes[] = {
+    /* "Reserved"" */
+    { "  UDEF",              "udef",   0xffff0000, 0x00000000, COUNT_NONE},
+    { "  SVE",               "sve",    0x1e000000, 0x04000000, COUNT_CLASS},
+    { "Reserved",            "res",    0x1e000000, 0x00000000, COUNT_CLASS},
+    /* Data Processing Immediate */
+    { "  PCrel addr",        "pcrel",  0x1f000000, 0x10000000, COUNT_CLASS},
+    { "  Add/Sub (imm,tags)","asit",   0x1f800000, 0x11800000, COUNT_CLASS},
+    { "  Add/Sub (imm)",     "asi",    0x1f000000, 0x11000000, COUNT_CLASS},
+    { "  Logical (imm)",     "logi",   0x1f800000, 0x12000000, COUNT_CLASS},
+    { "  Move Wide (imm)",   "movwi",  0x1f800000, 0x12800000, COUNT_CLASS},
+    { "  Bitfield",          "bitf",   0x1f800000, 0x13000000, COUNT_CLASS},
+    { "  Extract",           "extr",   0x1f800000, 0x13800000, COUNT_CLASS},
+    { "Data Proc Imm",       "dpri",   0x1c000000, 0x10000000, COUNT_CLASS},
+    /* Branches */
+    { "  Cond Branch (imm)", "cndb",   0xfe000000, 0x54000000, COUNT_CLASS},
+    { "  Exception Gen",     "excp",   0xff000000, 0xd4000000, COUNT_CLASS},
+    { "    NOP",             "nop",    0xffffffff, 0xd503201f, COUNT_NONE},
+    { "  Hints",             "hint",   0xfffff000, 0xd5032000, COUNT_CLASS},
+    { "  Barriers",          "barr",   0xfffff000, 0xd5033000, COUNT_CLASS},
+    { "  PSTATE",            "psta",   0xfff8f000, 0xd5004000, COUNT_CLASS},
+    { "  System Insn",       "sins",   0xffd80000, 0xd5080000, COUNT_CLASS},
+    { "  System Reg",        "sreg",   0xffd00000, 0xd5100000, COUNT_CLASS},
+    { "  Branch (reg)",      "breg",   0xfe000000, 0xd6000000, COUNT_CLASS},
+    { "  Branch (imm)",      "bimm",   0x7c000000, 0x14000000, COUNT_CLASS},
+    { "  Cmp & Branch",      "cmpb",   0x7e000000, 0x34000000, COUNT_CLASS},
+    { "  Tst & Branch",      "tstb",   0x7e000000, 0x36000000, COUNT_CLASS},
+    { "Branches",            "branch", 0x1c000000, 0x14000000, COUNT_CLASS},
+    /* Loads and Stores */
+    { "  AdvSimd ldstmult",  "advlsm", 0xbfbf0000, 0x0c000000, COUNT_CLASS},
+    { "  AdvSimd ldstmult++","advlsmp",0xbfb00000, 0x0c800000, COUNT_CLASS},
+    { "  AdvSimd ldst",      "advlss", 0xbf9f0000, 0x0d000000, COUNT_CLASS},
+    { "  AdvSimd ldst++",    "advlssp",0xbf800000, 0x0d800000, COUNT_CLASS},
+    { "  ldst excl",         "ldstx",  0x3f000000, 0x08000000, COUNT_CLASS},
+    { "    Prefetch",        "prfm",   0xff000000, 0xd8000000, COUNT_CLASS},
+    { "  Load Reg (lit)",    "ldlit",  0x1b000000, 0x18000000, COUNT_CLASS},
+    { "  ldst noalloc pair", "ldstnap",0x3b800000, 0x28000000, COUNT_CLASS},
+    { "  ldst pair",         "ldstp",  0x38000000, 0x28000000, COUNT_CLASS},
+    { "  ldst reg",          "ldstr",  0x3b200000, 0x38000000, COUNT_CLASS},
+    { "  Atomic ldst",       "atomic", 0x3b200c00, 0x38200000, COUNT_CLASS},
+    { "  ldst reg (reg off)","ldstro", 0x3b200b00, 0x38200800, COUNT_CLASS},
+    { "  ldst reg (pac)",    "ldstpa", 0x3b200200, 0x38200800, COUNT_CLASS},
+    { "  ldst reg (imm)",    "ldsti",  0x3b000000, 0x39000000, COUNT_CLASS},
+    { "Loads & Stores",      "ldst",   0x0a000000, 0x08000000, COUNT_CLASS},
+    /* Data Processing Register */
+    { "Data Proc Reg",       "dprr",   0x0e000000, 0x0a000000, COUNT_CLASS},
+    /* Scalar FP */
+    { "Scalar FP ",          "fpsimd", 0x0e000000, 0x0e000000, COUNT_CLASS},
+    /* Unclassified */
+    { "Unclassified",        "unclas", 0x00000000, 0x00000000, COUNT_CLASS},
+};
+
+static InsnClassExecCount sparc32_insn_classes[] = {
+    { "Call",                "call",   0xc0000000, 0x40000000, COUNT_CLASS},
+    { "Branch ICond",        "bcc",    0xc1c00000, 0x00800000, COUNT_CLASS},
+    { "Branch Fcond",        "fbcc",   0xc1c00000, 0x01800000, COUNT_CLASS},
+    { "SetHi",               "sethi",  0xc1c00000, 0x01000000, COUNT_CLASS},
+    { "FPU ALU",             "fpu",    0xc1f00000, 0x81a00000, COUNT_CLASS},
+    { "ALU",                 "alu",    0xc0000000, 0x80000000, COUNT_CLASS},
+    { "Load/Store",          "ldst",   0xc0000000, 0xc0000000, COUNT_CLASS},
+    /* Unclassified */
+    { "Unclassified",        "unclas", 0x00000000, 0x00000000, COUNT_INDIVIDUAL},
+};
+
+static InsnClassExecCount sparc64_insn_classes[] = {
+    { "SetHi & Branches",     "op0",   0xc0000000, 0x00000000, COUNT_CLASS},
+    { "Call",                 "op1",   0xc0000000, 0x40000000, COUNT_CLASS},
+    { "Arith/Logical/Move",   "op2",   0xc0000000, 0x80000000, COUNT_CLASS},
+    { "Arith/Logical/Move",   "op3",   0xc0000000, 0xc0000000, COUNT_CLASS},
+    /* Unclassified */
+    { "Unclassified",        "unclas", 0x00000000, 0x00000000, COUNT_INDIVIDUAL},
+};
+
+/* Default matcher for currently unclassified architectures */
+static InsnClassExecCount default_insn_classes[] = {
+    { "Unclassified",        "unclas", 0x00000000, 0x00000000, COUNT_INDIVIDUAL},
+};
+
+typedef struct {
+    const char *qemu_target;
+    InsnClassExecCount *table;
+    int table_sz;
+} ClassSelector;
+
+static ClassSelector class_tables[] =
+{
+    { "aarch64", aarch64_insn_classes, ARRAY_SIZE(aarch64_insn_classes) },
+    { "sparc",   sparc32_insn_classes, ARRAY_SIZE(sparc32_insn_classes) },
+    { "sparc64", sparc64_insn_classes, ARRAY_SIZE(sparc64_insn_classes) },
+    { NULL, default_insn_classes, ARRAY_SIZE(default_insn_classes) },
+};
+
+static InsnClassExecCount *class_table;
+static int class_table_sz;
+
+static gint cmp_exec_count(gconstpointer a, gconstpointer b)
+{
+    InsnExecCount *ea = (InsnExecCount *) a;
+    InsnExecCount *eb = (InsnExecCount *) b;
+    return ea->count > eb->count ? -1 : 1;
+}
+
+static void plugin_exit(qemu_plugin_id_t id, void *p)
+{
+    g_autoptr(GString) report = g_string_new("Instruction Classes:\n");
+    int i;
+    GList *counts;
+    InsnClassExecCount *class = NULL;
+
+    for (i = 0; i < class_table_sz; i++) {
+        class = &class_table[i];
+        switch (class->what) {
+        case COUNT_CLASS:
+            if (class->count || verbose) {
+                g_string_append_printf(report, "Class: %-24s\t(%ld hits)\n",
+                                       class->class,
+                                       class->count);
+            }
+            break;
+        case COUNT_INDIVIDUAL:
+            g_string_append_printf(report, "Class: %-24s\tcounted individually\n",
+                                   class->class);
+            break;
+        case COUNT_NONE:
+            g_string_append_printf(report, "Class: %-24s\tnot counted\n",
+                                   class->class);
+            break;
+        default:
+            break;
+        }
+    }
+
+    counts = g_hash_table_get_values(insns);
+    if (counts && g_list_next(counts)) {
+        GList *it;
+
+        g_string_append_printf(report,"Individual Instructions:\n");
+
+        it = g_list_sort(counts, cmp_exec_count);
+
+        for (i = 0; i < limit && it->next; i++, it = it->next) {
+            InsnExecCount *rec = (InsnExecCount *) it->data;
+            g_string_append_printf(report, "Instr: %-24s\t(%ld hits)\t(op=%#08x/%s)\n",
+                                   rec->insn,
+                                   rec->count,
+                                   rec->opcode,
+                                   rec->class ?
+                                   rec->class->class : "un-categorised");
+        }
+        g_list_free(it);
+    }
+
+    qemu_plugin_outs(report->str);
+}
+
+static void plugin_init(void)
+{
+    insns = g_hash_table_new(NULL, g_direct_equal);
+}
+
+static void vcpu_insn_exec_before(unsigned int cpu_index, void *udata)
+{
+    uint64_t *count = (uint64_t *) udata;
+    (*count)++;
+}
+
+static uint64_t * find_counter(struct qemu_plugin_insn *insn)
+{
+    int i;
+    uint64_t *cnt = NULL;
+    uint32_t opcode;
+    InsnClassExecCount *class = NULL;
+
+    /*
+     * We only match the first 32 bits of the instruction which is
+     * fine for most RISCs but a bit limiting for CISC architectures.
+     * They would probably benefit from a more tailored plugin.
+     * However we can fall back to individual instruction counting.
+     */
+    opcode = *((uint32_t *)qemu_plugin_insn_data(insn));
+
+    for (i = 0; !cnt && i < class_table_sz; i++) {
+        class = &class_table[i];
+        uint32_t masked_bits = opcode & class->mask;
+        if (masked_bits == class->pattern) {
+            break;
+        }
+    }
+
+    g_assert(class);
+
+    switch (class->what) {
+    case COUNT_NONE:
+        return NULL;
+    case COUNT_CLASS:
+        return &class->count;
+    case COUNT_INDIVIDUAL:
+    {
+        InsnExecCount *icount;
+
+        g_mutex_lock(&lock);
+        icount = (InsnExecCount *) g_hash_table_lookup(insns,
+                                                       GUINT_TO_POINTER(opcode));
+
+        if (!icount) {
+            icount = g_new0(InsnExecCount, 1);
+            icount->opcode = opcode;
+            icount->insn = qemu_plugin_insn_disas(insn);
+            icount->class = class;
+
+            g_hash_table_insert(insns, GUINT_TO_POINTER(opcode),
+                                (gpointer) icount);
+        }
+        g_mutex_unlock(&lock);
+
+        return &icount->count;
+    }
+    default:
+        g_assert_not_reached();
+    }
+
+    return NULL;
+}
+
+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++) {
+        uint64_t *cnt;
+        struct qemu_plugin_insn *insn = qemu_plugin_tb_get_insn(tb, i);
+        cnt = find_counter(insn);
+
+        if (cnt) {
+            if (do_inline) {
+                qemu_plugin_register_vcpu_insn_exec_inline(
+                    insn, QEMU_PLUGIN_INLINE_ADD_U64, cnt, 1);
+            } else {
+                qemu_plugin_register_vcpu_insn_exec_cb(
+                    insn, vcpu_insn_exec_before, QEMU_PLUGIN_CB_NO_REGS, cnt);
+            }
+        }
+    }
+}
+
+QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id,
+                                           const qemu_info_t *info,
+                                           int argc, char **argv)
+{
+    int i;
+
+    /* Select a class table appropriate to the guest architecture */
+    for (i = 0; i < ARRAY_SIZE(class_tables); i++) {
+        ClassSelector *entry = &class_tables[i];
+        if (!entry->qemu_target ||
+            strcmp(entry->qemu_target, info->target_name) == 0) {
+            class_table = entry->table;
+            class_table_sz = entry->table_sz;
+            break;
+        }
+    }
+
+    for (i = 0; i < argc; i++) {
+        char *p = argv[i];
+        if (strcmp(p, "inline") == 0) {
+            do_inline = true;
+        } else if (strcmp(p, "verbose") == 0) {
+            verbose = true;
+        } else {
+            int j;
+            CountType type = COUNT_INDIVIDUAL;
+            if (*p == '!') {
+                type = COUNT_NONE;
+                p++;
+            }
+            for (j = 0; j < class_table_sz; j++) {
+                if (strcmp(p, class_table[j].opt) == 0) {
+                    class_table[j].what = type;
+                    break;
+                }
+            }
+        }
+    }
+
+    plugin_init();
+
+    qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans);
+    qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
+    return 0;
+}