Re: [PATCH v1 1/2] perf expr: Make the evaluation of & and | logical and lazy
From: Ian Rogers
Date: Mon Jun 05 2023 - 13:32:37 EST
On Thu, May 18, 2023 at 12:47 PM Liang, Kan <kan.liang@xxxxxxxxxxxxxxx> wrote:
>
>
>
> On 2023-05-04 3:58 p.m., Ian Rogers wrote:
> > Currently the & and | operators are only used in metric thresholds
> > like (from the tma_retiring metric):
> > tma_retiring > 0.7 | tma_heavy_operations > 0.1
> >
> > Thresholds are always computed when present, but a lack events may
> > mean the threshold can't be computed. This happens with the option
> > --metric-no-threshold for say the metric tma_retiring on Tigerlake
> > model CPUs. To fully compute the threshold tma_heavy_operations is
> > needed and it needs the extra events of IDQ.MS_UOPS,
> > UOPS_DECODED.DEC0, cpu/UOPS_DECODED.DEC0,cmask=1/ and
> > IDQ.MITE_UOPS. So --metric-no-threshold is a useful option to reduce
> > the number of events needed and potentially multiplexing of events.
> >
> > Rather than just fail threshold computations like this, we may know a
> > result from just the left or right-hand side. So, for tma_retiring if
> > its value is "> 0.7" we know it is over the threshold. This allows the
> > metric to have the threshold coloring, when possible, without all the
> > counters being programmed.
> >
> > Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> > ---
>
> The patch works well on my machine.
>
> Tested-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
>
> Thanks,
> Kan
Arnaldo, could we take this set?
Thanks,
Ian
> > tools/perf/tests/expr.c | 40 +++++++++++++++++++
> > tools/perf/util/expr.y | 86 +++++++++++++++++++++++++++++++++--------
> > 2 files changed, 109 insertions(+), 17 deletions(-)
> >
> > diff --git a/tools/perf/tests/expr.c b/tools/perf/tests/expr.c
> > index cbf0e0c74906..45c7fedb797a 100644
> > --- a/tools/perf/tests/expr.c
> > +++ b/tools/perf/tests/expr.c
> > @@ -184,6 +184,46 @@ static int test__expr(struct test_suite *t __maybe_unused, int subtest __maybe_u
> > NULL, ctx) == 0);
> > TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 0);
> >
> > + /* The expression is a constant 0.0 without needing to evaluate EVENT1. */
> > + expr__ctx_clear(ctx);
> > + TEST_ASSERT_VAL("find ids",
> > + expr__find_ids("0 & EVENT1 > 0", NULL, ctx) == 0);
> > + TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 0);
> > + expr__ctx_clear(ctx);
> > + TEST_ASSERT_VAL("find ids",
> > + expr__find_ids("EVENT1 > 0 & 0", NULL, ctx) == 0);
> > + TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 0);
> > + expr__ctx_clear(ctx);
> > + TEST_ASSERT_VAL("find ids",
> > + expr__find_ids("1 & EVENT1 > 0", NULL, ctx) == 0);
> > + TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 1);
> > + TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids, "EVENT1", &val_ptr));
> > + expr__ctx_clear(ctx);
> > + TEST_ASSERT_VAL("find ids",
> > + expr__find_ids("EVENT1 > 0 & 1", NULL, ctx) == 0);
> > + TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 1);
> > + TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids, "EVENT1", &val_ptr));
> > +
> > + /* The expression is a constant 1.0 without needing to evaluate EVENT1. */
> > + expr__ctx_clear(ctx);
> > + TEST_ASSERT_VAL("find ids",
> > + expr__find_ids("1 | EVENT1 > 0", NULL, ctx) == 0);
> > + TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 0);
> > + expr__ctx_clear(ctx);
> > + TEST_ASSERT_VAL("find ids",
> > + expr__find_ids("EVENT1 > 0 | 1", NULL, ctx) == 0);
> > + TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 0);
> > + expr__ctx_clear(ctx);
> > + TEST_ASSERT_VAL("find ids",
> > + expr__find_ids("0 | EVENT1 > 0", NULL, ctx) == 0);
> > + TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 1);
> > + TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids, "EVENT1", &val_ptr));
> > + expr__ctx_clear(ctx);
> > + TEST_ASSERT_VAL("find ids",
> > + expr__find_ids("EVENT1 > 0 | 0", NULL, ctx) == 0);
> > + TEST_ASSERT_VAL("find ids", hashmap__size(ctx->ids) == 1);
> > + TEST_ASSERT_VAL("find ids", hashmap__find(ctx->ids, "EVENT1", &val_ptr));
> > +
> > /* Test toplogy constants appear well ordered. */
> > expr__ctx_clear(ctx);
> > TEST_ASSERT_VAL("#num_cpus", expr__parse(&num_cpus, ctx, "#num_cpus") == 0);
> > diff --git a/tools/perf/util/expr.y b/tools/perf/util/expr.y
> > index 250e444bf032..6b110f9f95c9 100644
> > --- a/tools/perf/util/expr.y
> > +++ b/tools/perf/util/expr.y
> > @@ -123,20 +123,6 @@ static struct ids handle_id(struct expr_parse_ctx *ctx, char *id,
> > * constant value using OP. Its invariant that there are no ids. If computing
> > * ids for non-constants union the set of IDs that must be computed.
> > */
> > -#define BINARY_LONG_OP(RESULT, OP, LHS, RHS) \
> > - if (!compute_ids || (is_const(LHS.val) && is_const(RHS.val))) { \
> > - assert(LHS.ids == NULL); \
> > - assert(RHS.ids == NULL); \
> > - if (isnan(LHS.val) || isnan(RHS.val)) { \
> > - RESULT.val = NAN; \
> > - } else { \
> > - RESULT.val = (long)LHS.val OP (long)RHS.val; \
> > - } \
> > - RESULT.ids = NULL; \
> > - } else { \
> > - RESULT = union_expr(LHS, RHS); \
> > - }
> > -
> > #define BINARY_OP(RESULT, OP, LHS, RHS) \
> > if (!compute_ids || (is_const(LHS.val) && is_const(RHS.val))) { \
> > assert(LHS.ids == NULL); \
> > @@ -213,9 +199,75 @@ expr: NUMBER
> > }
> > | ID { $$ = handle_id(ctx, $1, compute_ids, /*source_count=*/false); }
> > | SOURCE_COUNT '(' ID ')' { $$ = handle_id(ctx, $3, compute_ids, /*source_count=*/true); }
> > -| expr '|' expr { BINARY_LONG_OP($$, |, $1, $3); }
> > -| expr '&' expr { BINARY_LONG_OP($$, &, $1, $3); }
> > -| expr '^' expr { BINARY_LONG_OP($$, ^, $1, $3); }
> > +| expr '|' expr
> > +{
> > + if (is_const($1.val) && is_const($3.val)) {
> > + assert($1.ids == NULL);
> > + assert($3.ids == NULL);
> > + $$.ids = NULL;
> > + $$.val = (fpclassify($1.val) == FP_ZERO && fpclassify($3.val) == FP_ZERO) ? 0 : 1;
> > + } else if (is_const($1.val)) {
> > + assert($1.ids == NULL);
> > + if (fpclassify($1.val) == FP_ZERO) {
> > + $$ = $3;
> > + } else {
> > + $$.val = 1;
> > + $$.ids = NULL;
> > + ids__free($3.ids);
> > + }
> > + } else if (is_const($3.val)) {
> > + assert($3.ids == NULL);
> > + if (fpclassify($3.val) == FP_ZERO) {
> > + $$ = $1;
> > + } else {
> > + $$.val = 1;
> > + $$.ids = NULL;
> > + ids__free($1.ids);
> > + }
> > + } else {
> > + $$ = union_expr($1, $3);
> > + }
> > +}
> > +| expr '&' expr
> > +{
> > + if (is_const($1.val) && is_const($3.val)) {
> > + assert($1.ids == NULL);
> > + assert($3.ids == NULL);
> > + $$.val = (fpclassify($1.val) != FP_ZERO && fpclassify($3.val) != FP_ZERO) ? 1 : 0;
> > + $$.ids = NULL;
> > + } else if (is_const($1.val)) {
> > + assert($1.ids == NULL);
> > + if (fpclassify($1.val) != FP_ZERO) {
> > + $$ = $3;
> > + } else {
> > + $$.val = 0;
> > + $$.ids = NULL;
> > + ids__free($3.ids);
> > + }
> > + } else if (is_const($3.val)) {
> > + assert($3.ids == NULL);
> > + if (fpclassify($3.val) != FP_ZERO) {
> > + $$ = $1;
> > + } else {
> > + $$.val = 0;
> > + $$.ids = NULL;
> > + ids__free($1.ids);
> > + }
> > + } else {
> > + $$ = union_expr($1, $3);
> > + }
> > +}
> > +| expr '^' expr
> > +{
> > + if (is_const($1.val) && is_const($3.val)) {
> > + assert($1.ids == NULL);
> > + assert($3.ids == NULL);
> > + $$.val = (fpclassify($1.val) == FP_ZERO) != (fpclassify($3.val) == FP_ZERO) ? 1 : 0;
> > + $$.ids = NULL;
> > + } else {
> > + $$ = union_expr($1, $3);
> > + }
> > +}
> > | expr '<' expr { BINARY_OP($$, <, $1, $3); }
> > | expr '>' expr { BINARY_OP($$, >, $1, $3); }
> > | expr '+' expr { BINARY_OP($$, +, $1, $3); }