From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 368BA3858D28 for ; Fri, 5 Nov 2021 18:16:21 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 368BA3858D28 Received: from mail-ua1-f72.google.com (mail-ua1-f72.google.com [209.85.222.72]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-402-aCNIl0lfOr-ma5_y77xscQ-1; Fri, 05 Nov 2021 14:16:19 -0400 X-MC-Unique: aCNIl0lfOr-ma5_y77xscQ-1 Received: by mail-ua1-f72.google.com with SMTP id j29-20020ab0185d000000b002cbb3c4660bso4861228uag.23 for ; Fri, 05 Nov 2021 11:16:19 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=DOxicVlxFXSrgEhbnTYh/OU3V974a0DRM1vGRhoWYDo=; b=ISz/i6pAc4zh7PIgkOiU9fSl57yPUI829hRW+jp7GE87uFrVmKU0LBvt0U+xO3XqJC ZZyN/ZVfkUJ5qwXHLFG2VGbYQkPFCo5LfvjfhNNU0M5x6ivI4b4kBsh3LpbMvjFtgO4L gEwz5g4RLvUIsmlxN5FslwhpT9R/405CoUI2J2Fjz+dR2LPX+Qhd7/y+tJC+h/Z7j1/f CloKWqRI+/bTsHr7YOOOssWnxKj43Y3LQ56KnHeq+EVxkdhiLDRcZO4UA3sqH958lH6L BhL27nQomOartw99rL1PNLOlX2HD/1iyb2uJtvpqP6coNtm6KkSgm/vOfFJaGEwnXAQm Y8WA== X-Gm-Message-State: AOAM531gChAW9r4xi0Q1UlHWmIMfO33sctI0ImfqnoTPtpPu9PzU2Ab/ moCveubapIvLuBT0zxJmznpJTlqH0vEf1Qovm5vKT8T6w39v973zjNSpyR0UdfIfdlaLWjbAo91 9hrSiirYp7Mho8nbP2aE0sxcvi1dsRC4= X-Received: by 2002:a05:6122:c92:: with SMTP id ba18mr40638255vkb.21.1636136179169; Fri, 05 Nov 2021 11:16:19 -0700 (PDT) X-Google-Smtp-Source: ABdhPJzUlHqBglfJ5QlznPgR6h62Ct8OS2EyrBYEin4LVUJNuak9LBn0YRtL/X/ak49/ZvT1M2Pv8MOQZ+Rzqn0bX9w= X-Received: by 2002:a05:6122:c92:: with SMTP id ba18mr40638219vkb.21.1636136178920; Fri, 05 Nov 2021 11:16:18 -0700 (PDT) MIME-Version: 1.0 References: <00a3f87e-77d4-39d4-8385-4207ab271bb1@linux.ibm.com> <016e938f-d115-7e0d-1d2f-cf9495708e41@linux.ibm.com> In-Reply-To: <016e938f-d115-7e0d-1d2f-cf9495708e41@linux.ibm.com> From: Jonathan Wakely Date: Fri, 5 Nov 2021 18:16:07 +0000 Message-ID: Subject: Re: [PATCH v2] libstdc++: Add support for POWER9 DARN instruction to std::random_device To: Bill Schmidt Cc: "libstdc++" , gcc Patches , Segher Boessenkool X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-7.1 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, HTML_MESSAGE, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H2, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.29 X-BeenThere: libstdc++@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libstdc++ mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 05 Nov 2021 18:16:22 -0000 On Fri, 5 Nov 2021 at 13:20, Bill Schmidt wrote: > > On 11/5/21 7:44 AM, Jonathan Wakely wrote: > > On Thu, 4 Nov 2021 at 20:44, Bill Schmidt wrote: For posterity: This > was discussed briefly on IRC, and Segher approved with some simplifications > and a request to implement a fail/retry check. Here's what I have now. No > more assembler check > > On Thu, 4 Nov 2021 at 20:44, Bill Schmidt wrote: > > > > For posterity: This was discussed briefly on IRC, and Segher > approved with some > > simplifications and a request to implement a fail/retry check. > > > > > > Here's what I have now. No more assembler check in configure, and it > uses the 64-bit __builtin_darn() and truncates it to 32-bit, or retries (up > to 100 times) if it fails. > > > > I'm doing some more testing now. > > > Those changes look good from my perspective. Thanks again for this work! > (Not a maintainer, blah blah...) > I changed the number of retries to 10 and pushed it to trunk.