From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-Status: No, score=-4.2 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,MAILING_LIST_MULTI, SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server2.sourceware.org [IPv6:2620:52:3:1:0:246e:9693:128c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id 149C51F4B4 for ; Wed, 14 Oct 2020 01:32:28 +0000 (UTC) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 29E9B3850407; Wed, 14 Oct 2020 01:32:27 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 29E9B3850407 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1602639147; bh=TThnxuP5qZl/DUGsDOHNRx7o/r94QfuvJgUnN2Lro84=; h=To:Subject:In-Reply-To:Date:List-Id:List-Unsubscribe:List-Archive: List-Post:List-Help:List-Subscribe:From:Reply-To:Cc:From; b=Rt8sTFkg7uLqrDMJDlx2YUkj/Io89i5NycuH5b580bMFJtz0h/+e4bVKj2AmEk6iZ 7s4Lg847k8QFaFK4pYyx0ieEJkR+d6GapFqxXXdvYQ1bka/O1wkdXNQa3jeFONmYiA 1ECCnD3OYdVj66oGE6P00HYiFrzn8vLBy5TC2lLA= Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [63.128.21.124]) by sourceware.org (Postfix) with ESMTP id 63044385700E for ; Wed, 14 Oct 2020 01:32:23 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 63044385700E Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-426-0eNfLh-7Pw6oyVV978KL2Q-1; Tue, 13 Oct 2020 21:32:21 -0400 X-MC-Unique: 0eNfLh-7Pw6oyVV978KL2Q-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0F2A91007463; Wed, 14 Oct 2020 01:32:20 +0000 (UTC) Received: from greed.delorie.com (ovpn-112-151.rdu2.redhat.com [10.10.112.151]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D573D2C31E; Wed, 14 Oct 2020 01:32:19 +0000 (UTC) Received: from greed.delorie.com.redhat.com (localhost [127.0.0.1]) by greed.delorie.com (8.14.7/8.14.7) with ESMTP id 09E1WIRr008311; Tue, 13 Oct 2020 21:32:18 -0400 To: Siddhesh Poyarekar Subject: Re: [v2] New benchtest: pthread locks In-Reply-To: <95b4cd6d-3f74-c26d-aad3-fadd1a0fbf5d@gotplt.org> (message from Siddhesh Poyarekar on Wed, 14 Oct 2020 06:57:13 +0530) Date: Tue, 13 Oct 2020 21:32:18 -0400 Message-ID: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: DJ Delorie via Libc-alpha Reply-To: DJ Delorie Cc: libc-alpha@sourceware.org Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" Siddhesh Poyarekar writes: >> +/* The point of this benchmark is to measure the overhead of an empty >> + critical section or a small critical section. This is never going >> + to be indicative of real application performance. Instead we are >> + trying to benchmark the effects of the compiler and the runtime >> + coupled with a particular set of hardware atomic operations. >> + The numbers from this benchmark should be taken with a massive gain >> + of salt and viewed through the eyes of expert reviewers. */ > > That is a great comment. All benchmarks should have a goal set like > this so that it is clear to whoever evaluates them that just getting > better numbers in a specific benchmark is not good enough and one would > have to evaluate why a certain set of results supports their optimisation. IIRC Carlos provided that text in one of his internal pre-reviews, so kudos to him. The remainder of the comments are mine though.