On 1/24/22 21:16, Alex Bennée wrote:
> This adds simple instruction matching to the libinsn.so plugin which
> is useful for examining the execution distance between instructions.
> For example to track how often we flush in ARM due to TLB updates:
>
> -plugin ./tests/plugin/libinsn.so,match=tlbi
>
> which leads to output like this:
>
> 0xffffffc01018fa00, tlbi aside1is, x0, 339, 32774 match hits, 23822 since
> last, avg 47279
> 0xffffffc01018fa00, tlbi aside1is, x0, 340, 32775 match hits, 565051 since
> last, avg 47295
> 0xffffffc0101915a4, tlbi vae1is, x0, 155, 32776 match hits, 151135 since
> last, avg 47298
> 0xffffffc01018fc60, tlbi vae1is, x4, 224, 32777 match hits, 814 since
> last, avg 47297
> 0xffffffc010194a44, tlbi vale1is, x1, 8835, 32778 match hits, 52027 since
> last, avg 47297
> 0xffffffc010194a44, tlbi vale1is, x1, 8836, 32779 match hits, 8347 since
> last, avg 47296
> 0xffffffc010194a44, tlbi vale1is, x1, 8837, 32780 match hits, 33677 since
> last, avg 47295
Just nitpicking the output below.
> showing we do some sort of TLBI invalidation every 47 thousand
> instructions.
>
> Cc: Vasilev Oleg <vasilev.o...@huawei.com>
> Cc: Richard Henderson <richard.hender...@linaro.org>
> Cc: Emilio Cota <c...@braap.org>
> Signed-off-by: Alex Bennée <alex.ben...@linaro.org>
> ---
> tests/plugin/insn.c | 88 ++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 87 insertions(+), 1 deletion(-)
> +static void vcpu_insn_matched_exec_before(unsigned int cpu_index, void
> *udata)
> +{
> + unsigned int i = cpu_index % MAX_CPUS;
> + Instruction *insn = (Instruction *) udata;
> + Match *match = insn->match;
> + g_autoptr(GString) ts = g_string_new("");
> +
> + insn->hits++;
> + g_string_append_printf(ts, "0x%" PRIx64 ", %s, % "PRId64,
> + insn->vaddr, insn->disas, insn->hits);
Maybe use something else the ',' to split last arg (hits)? \t or --?
Otherwise it seems part of the decoded instr.
> +
> + uint64_t icount = counts[i].insn_count;
> + uint64_t delta = icount - match->last_hit[i];
> +
> + match->hits[i]++;
> + match->total_delta[i] += delta;
> +
> + g_string_append_printf(ts,
> + ", %"PRId64" match hits, %"PRId64
Maybe prefix delta with '+'.
> + " since last, avg %"PRId64"\n",
> + match->hits[i], delta,
> + match->total_delta[i] / match->hits[i]);
> +
> + match->last_hit[i] = icount;
> +
> + qemu_plugin_outs(ts->str);
> +
> + g_ptr_array_add(match->history[i], insn);
> +}
