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SubjectRe: [PATCH v1 07/15] perf, tools: Expression parser enhancements for metrics
On Mon, Jul 24, 2017 at 04:40:07PM -0700, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
>
> Enhance the expression parser for more complex metric formulas.
>
> - Support python style IF ELSE operators
> - Support MIN/MAX operations
> - Support | & ^ operators
> - Minor cleanups and fixes
> - Add an #SMT_On magic variable for formulas that depend on the SMT
> status.
> - Support an \ escape for operators. This allows to specify event names
> like c2-residency

please state some examples of this

thanks,
jirka

> - Support @ as an alternative for / to be able to specify pmus without
> conflicts with operators (like msr/tsc/ as msr@tsc@)
>
> Signed-off-by: Andi Kleen <ak@linux.intel.com>
> ---
> tools/perf/tests/expr.c | 5 ++++
> tools/perf/util/expr.y | 61 ++++++++++++++++++++++++++++++++++++++++++++-----
> 2 files changed, 60 insertions(+), 6 deletions(-)
>
> diff --git a/tools/perf/tests/expr.c b/tools/perf/tests/expr.c
> index 6c6a3749aaf6..e75365098f23 100644
> --- a/tools/perf/tests/expr.c
> +++ b/tools/perf/tests/expr.c
> @@ -31,6 +31,11 @@ int test__expr(int subtest __maybe_unused)
> ret |= test(&ctx, "(BAR/2)%2", 1);
> ret |= test(&ctx, "1 - -4", 5);
> ret |= test(&ctx, "(FOO-1)*2 + (BAR/2)%2 - -4", 5);
> + ret |= test(&ctx, "1-1 | 1", 1);
> + ret |= test(&ctx, "1-1 & 1", 0);
> + ret |= test(&ctx, "min(1,2) + 1", 2);
> + ret |= test(&ctx, "max(1,2) + 1", 3);
> + ret |= test(&ctx, "1+1 if 3*4 else 0", 2);
>
> if (ret)
> return ret;
> diff --git a/tools/perf/util/expr.y b/tools/perf/util/expr.y
> index 953e65ba2cc7..5753c4f21534 100644
> --- a/tools/perf/util/expr.y
> +++ b/tools/perf/util/expr.y
> @@ -4,6 +4,7 @@
> #include "util/debug.h"
> #define IN_EXPR_Y 1
> #include "expr.h"
> +#include "smt.h"
> #include <string.h>
>
> #define MAXIDLEN 256
> @@ -22,13 +23,15 @@
>
> %token <num> NUMBER
> %token <id> ID
> +%token MIN MAX IF ELSE SMT_ON
> +%left MIN MAX IF
> %left '|'
> %left '^'
> %left '&'
> %left '-' '+'
> %left '*' '/' '%'
> %left NEG NOT
> -%type <num> expr
> +%type <num> expr if_expr
>
> %{
> static int expr__lex(YYSTYPE *res, const char **pp);
> @@ -57,7 +60,12 @@ static int lookup_id(struct parse_ctx *ctx, char *id, double *val)
> %}
> %%
>
> -all_expr: expr { *final_val = $1; }
> +all_expr: if_expr { *final_val = $1; }
> + ;
> +
> +if_expr:
> + expr IF expr ELSE expr { $$ = $3 ? $1 : $5; }
> + | expr
> ;
>
> expr: NUMBER
> @@ -66,13 +74,19 @@ expr: NUMBER
> YYABORT;
> }
> }
> + | expr '|' expr { $$ = (long)$1 | (long)$3; }
> + | expr '&' expr { $$ = (long)$1 & (long)$3; }
> + | expr '^' expr { $$ = (long)$1 ^ (long)$3; }
> | expr '+' expr { $$ = $1 + $3; }
> | expr '-' expr { $$ = $1 - $3; }
> | expr '*' expr { $$ = $1 * $3; }
> | expr '/' expr { if ($3 == 0) YYABORT; $$ = $1 / $3; }
> | expr '%' expr { if ((long)$3 == 0) YYABORT; $$ = (long)$1 % (long)$3; }
> | '-' expr %prec NEG { $$ = -$2; }
> - | '(' expr ')' { $$ = $2; }
> + | '(' if_expr ')' { $$ = $2; }
> + | MIN '(' expr ',' expr ')' { $$ = $3 < $5 ? $3 : $5; }
> + | MAX '(' expr ',' expr ')' { $$ = $3 > $5 ? $3 : $5; }
> + | SMT_ON { $$ = smt_on() > 0; }
> ;
>
> %%
> @@ -82,13 +96,47 @@ static int expr__symbol(YYSTYPE *res, const char *p, const char **pp)
> char *dst = res->id;
> const char *s = p;
>
> - while (isalnum(*p) || *p == '_' || *p == '.') {
> + if (*p == '#')
> + *dst++ = *p++;
> +
> + while (isalnum(*p) || *p == '_' || *p == '.' || *p == ':' || *p == '@' || *p == '\\') {
> if (p - s >= MAXIDLEN)
> return -1;
> - *dst++ = *p++;
> + /*
> + * Allow @ instead of / to be able to specify pmu/event/ without
> + * conflicts with normal division.
> + */
> + if (*p == '@')
> + *dst++ = '/';
> + else if (*p == '\\')
> + *dst++ = *++p;
> + else
> + *dst++ = *p;
> + p++;
> }
> *dst = 0;
> *pp = p;
> + dst = res->id;
> + switch (dst[0]) {
> + case 'm':
> + if (!strcmp(dst, "min"))
> + return MIN;
> + if (!strcmp(dst, "max"))
> + return MAX;
> + break;
> + case 'i':
> + if (!strcmp(dst, "if"))
> + return IF;
> + break;
> + case 'e':
> + if (!strcmp(dst, "else"))
> + return ELSE;
> + break;
> + case '#':
> + if (!strcasecmp(dst, "#smt_on"))
> + return SMT_ON;
> + break;
> + }
> return ID;
> }
>
> @@ -102,6 +150,7 @@ static int expr__lex(YYSTYPE *res, const char **pp)
> p++;
> s = p;
> switch (*p++) {
> + case '#':
> case 'a' ... 'z':
> case 'A' ... 'Z':
> return expr__symbol(res, p - 1, pp);
> @@ -151,7 +200,7 @@ int expr__find_other(const char *p, const char *one, const char ***other,
> err = 0;
> break;
> }
> - if (tok == ID && strcasecmp(one, val.id)) {
> + if (tok == ID && (!one || strcasecmp(one, val.id))) {
> if (num_other >= EXPR_MAX_OTHER - 1) {
> pr_debug("Too many extra events in %s\n", orig);
> break;
> --
> 2.9.4
>

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