Re: [PATCH v2 06/11] perf expr: parse numbers as doubles

kajoljain
2020-04-27T11:13:17Z

On 4/23/20 3:34 AM, Ian Rogers wrote:
> This is expected in expr.y and metrics use floating point values such as
> x86 broadwell IFetch_Line_Utilization.
>
> Fixes: 26226a97724d (perf expr: Move expr lexer to flex)
> Signed-off-by: Ian Rogers <irogers@google.com>
> ---
> tools/perf/util/expr.l | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/tools/perf/util/expr.l b/tools/perf/util/expr.l
> index 95bcf3629edf..0efda2ce2766 100644
> --- a/tools/perf/util/expr.l
> +++ b/tools/perf/util/expr.l
> @@ -10,12 +10,12 @@
> char *expr_get_text(yyscan_t yyscanner);
> YYSTYPE *expr_get_lval(yyscan_t yyscanner);
>
> -static int __value(YYSTYPE *yylval, char *str, int base, int token)
> +static double __value(YYSTYPE *yylval, char *str, int token)
> {
> - u64 num;
> + double num;
>
> errno = 0;
> - num = strtoull(str, NULL, base);
> + num = strtod(str, NULL);
> if (errno)
> return EXPR_ERROR;
>
> @@ -23,12 +23,12 @@ static int __value(YYSTYPE *yylval, char *str, int base, int token)
> return token;
> }
>
> -static int value(yyscan_t scanner, int base)
> +static int value(yyscan_t scanner)
> {
> YYSTYPE *yylval = expr_get_lval(scanner);
> char *text = expr_get_text(scanner);
>
> - return __value(yylval, text, base, NUMBER);
> + return __value(yylval, text, NUMBER);
> }
>
> /*
> @@ -68,7 +68,7 @@ static int str(yyscan_t scanner, int token)
> }
> %}
>
> -number [0-9]+
> +number [0-9]*\.?[0-9]+
>

Hi Ian,
In this patch I saw the parsing of expression with '+number [0-9]*\.?[0-9]+'
Could you please explain why '?' is introduced here, so that I can be sure that this is
not conflicting with my change to add '?'

In this patch : https://lkml.org/lkml/2020/4/1/1427
I have used '?' symbol as part of metric expression in order to replace '?' with runtime
parameter.

Thanks,
Kajol Jain

> sch [-,=]
> spec \\{sch}
> @@ -92,7 +92,7 @@ min { return MIN; }
> if { return IF; }
> else { return ELSE; }
> #smt_on { return SMT_ON; }
> -{number} { return value(yyscanner, 10); }
> +{number} { return value(yyscanner); }
> {symbol} { return str(yyscanner, ID); }
> "|" { return '|'; }
> "^" { return '^'; }
>