From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D10AC433EF for ; Wed, 15 Sep 2021 19:54:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41860610A6 for ; Wed, 15 Sep 2021 19:54:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231583AbhIOT4C (ORCPT ); Wed, 15 Sep 2021 15:56:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50652 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231562AbhIOT4C (ORCPT ); Wed, 15 Sep 2021 15:56:02 -0400 Received: from mail-qk1-x749.google.com (mail-qk1-x749.google.com [IPv6:2607:f8b0:4864:20::749]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C78AFC061574 for ; Wed, 15 Sep 2021 12:54:42 -0700 (PDT) Received: by mail-qk1-x749.google.com with SMTP id 23-20020a05620a071700b00426392c0e6eso7176912qkc.4 for ; Wed, 15 Sep 2021 12:54:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:in-reply-to:message-id:mime-version:references:subject:from:cc; bh=aeNnN9xag+ICPAe0ffKzWBBB/Z6CmxOcYPRHh7D2frs=; b=qIerQ+9u8w+7e+qc1Pt4BEtWWL4xi9o8Z0pshF/NwvFawnX2spGgfsa9wOdgOOK9XQ RsJjzY7WGt/x7Wfs3fZPhK7HV2XBvzYQhv2bGfwblwPJ+AxlvEq944N7y6+C/zP6st/K twrstG4QdSPG3LQcpZ+dcCdMORJbjS3Ap/fnWfckbmFtO9pZm6gHHt2z+NsiRWTxOh3N i1JHv9yIrsHipRryQvgavJikwchYg2qHfdG7ep7gkYP6fB7Fx4+dOei0JgekEhb01/g+ AxBKKH+J4nWVjPfNEtTSPGqEoxCFWJegufYxQbs+ajtcOyaU0QEDGRnDFLlHFR9Muinr y2iA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:cc; bh=aeNnN9xag+ICPAe0ffKzWBBB/Z6CmxOcYPRHh7D2frs=; b=ikcxZuGbWx4oLu9/kQ3QQZ9bMKpQZLRkwtpbUL8733kaIPJYeQJVldEIAs/qeLLNYJ FX9xTZUsl34QaAbotTJJGOGW7lqO2Q4gRFR/F9kAoXRILPE+fe2XM4U01zNHlTWHpd11 LGrn+vucVVKSIwX5nH/GBDkDYDPia2lN7275c3rfT5yQx59BTymuZk9p75WnGgpQ95iq 5EccGfOOM5fEx1HyVoP4o/UYNF4BpRSkrU5GDIUhvj29Quk7OAl36+ihrwKoeDHvun0r GsgIVbvGgw+6X8KRvs74mVyU3EU5o67OLtiKPHAH0JNVmTbnwWMxVfXZxsMQXmAKo/eo 8Enw== X-Gm-Message-State: AOAM530glMwwBFhuFuRjueICSdc/9wCEllrFhjwKZKziuPkkvE33antp 0jAjlLn4Kdo+tHcsAaunIkZggxYyjG+WcQp1Ww== X-Google-Smtp-Source: ABdhPJz+DW0EgPkGnJfyhBQPsr8CaKufz8imI6mY2o3UUZTSwYh/1vOOeISmx+9v9/HDzO4mxi5M1R98Grqs+py63A== X-Received: from kaleshsingh.c.googlers.com ([fda3:e722:ac3:cc00:14:4d90:c0a8:2145]) (user=kaleshsingh job=sendgmr) by 2002:a0c:f58a:: with SMTP id k10mr1752710qvm.62.1631735681948; Wed, 15 Sep 2021 12:54:41 -0700 (PDT) Date: Wed, 15 Sep 2021 19:52:46 +0000 In-Reply-To: <20210915195306.612966-1-kaleshsingh@google.com> Message-Id: <20210915195306.612966-3-kaleshsingh@google.com> Mime-Version: 1.0 References: <20210915195306.612966-1-kaleshsingh@google.com> X-Mailer: git-send-email 2.33.0.309.g3052b89438-goog Subject: [PATCH 2/5] tracing: Add division and multiplication support for hist triggers From: Kalesh Singh Cc: surenb@google.com, hridya@google.com, namhyung@kernel.org, Kalesh Singh , Jonathan Corbet , Steven Rostedt , Ingo Molnar , Shuah Khan , Tom Zanussi , Masami Hiramatsu , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Content-Type: text/plain; charset="UTF-8" To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Adds basic support for division and multiplication operations for hist trigger variable expressions. For simplicity this patch only supports, division and multiplication for a single operation expression (e.g. x=$a/$b), as currently expressions are always evaluated right to left. This can lead to some incorrect results: e.g. echo 'hist:keys=common_pid:x=8-4-2' >> event/trigger 8-4-2 should evaluate to 2 i.e. (8-4)-2 but currently x evaluate to 6 i.e. 8-(4-2) Multiplication and division in sub-expressions will work correctly, once correct operator precedence support is added (See next patch in this series). For the undefined case of division by 0, the histogram expression evaluates to (u64)(-1). Since this cannot be detected when the expression is created, it is the responsibility of the user to be aware and account for this possibility. Examples: echo 'hist:keys=common_pid:a=8,b=4,x=$a/$b' \ >> event/trigger echo 'hist:keys=common_pid:x=5*$b' \ >> event/trigger Signed-off-by: Kalesh Singh --- kernel/trace/trace_events_hist.c | 72 +++++++++++++++++++++++++++++++- 1 file changed, 71 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 2802b211ccf3..dc28eb6fc73a 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -99,6 +99,8 @@ enum field_op_id { FIELD_OP_PLUS, FIELD_OP_MINUS, FIELD_OP_UNARY_MINUS, + FIELD_OP_DIV, + FIELD_OP_MULT, }; /* @@ -287,6 +289,40 @@ static u64 hist_field_minus(struct hist_field *hist_field, return val1 - val2; } +static u64 hist_field_div(struct hist_field *hist_field, + struct tracing_map_elt *elt, + struct trace_buffer *buffer, + struct ring_buffer_event *rbe, + void *event) +{ + struct hist_field *operand1 = hist_field->operands[0]; + struct hist_field *operand2 = hist_field->operands[1]; + + u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event); + u64 val2 = operand2->fn(operand2, elt, buffer, rbe, event); + + /* Return -1 for the undefined case */ + if (!val2) + return -1; + + return val1 / val2; +} + +static u64 hist_field_mult(struct hist_field *hist_field, + struct tracing_map_elt *elt, + struct trace_buffer *buffer, + struct ring_buffer_event *rbe, + void *event) +{ + struct hist_field *operand1 = hist_field->operands[0]; + struct hist_field *operand2 = hist_field->operands[1]; + + u64 val1 = operand1->fn(operand1, elt, buffer, rbe, event); + u64 val2 = operand2->fn(operand2, elt, buffer, rbe, event); + + return val1 * val2; +} + static u64 hist_field_unary_minus(struct hist_field *hist_field, struct tracing_map_elt *elt, struct trace_buffer *buffer, @@ -1595,6 +1631,12 @@ static char *expr_str(struct hist_field *field, unsigned int level) case FIELD_OP_PLUS: strcat(expr, "+"); break; + case FIELD_OP_DIV: + strcat(expr, "/"); + break; + case FIELD_OP_MULT: + strcat(expr, "*"); + break; default: kfree(expr); return NULL; @@ -1610,7 +1652,7 @@ static int contains_operator(char *str) enum field_op_id field_op = FIELD_OP_NONE; char *op; - op = strpbrk(str, "+-"); + op = strpbrk(str, "+-/*"); if (!op) return FIELD_OP_NONE; @@ -1631,6 +1673,12 @@ static int contains_operator(char *str) case '+': field_op = FIELD_OP_PLUS; break; + case '/': + field_op = FIELD_OP_DIV; + break; + case '*': + field_op = FIELD_OP_MULT; + break; default: break; } @@ -2370,10 +2418,26 @@ static struct hist_field *parse_expr(struct hist_trigger_data *hist_data, case FIELD_OP_PLUS: sep = "+"; break; + case FIELD_OP_DIV: + sep = "/"; + break; + case FIELD_OP_MULT: + sep = "*"; + break; default: goto free; } + /* + * Multiplication and division are only supported in single operator + * expressions, since the expression is always evaluated from right + * to left. + */ + if ((field_op == FIELD_OP_DIV || field_op == FIELD_OP_MULT) && level > 0) { + hist_err(file->tr, HIST_ERR_TOO_MANY_SUBEXPR, errpos(str)); + return ERR_PTR(-EINVAL); + } + operand1_str = strsep(&str, sep); if (!operand1_str || !str) goto free; @@ -2445,6 +2509,12 @@ static struct hist_field *parse_expr(struct hist_trigger_data *hist_data, case FIELD_OP_PLUS: expr->fn = hist_field_plus; break; + case FIELD_OP_DIV: + expr->fn = hist_field_div; + break; + case FIELD_OP_MULT: + expr->fn = hist_field_mult; + break; default: ret = -EINVAL; goto free; -- 2.33.0.309.g3052b89438-goog