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-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-4.0 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id 8350B1F45F for ; Thu, 9 May 2019 15:46:20 +0000 (UTC) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:date:from:to:cc:subject:in-reply-to:message-id :references:mime-version:content-type; q=dns; s=default; b=Bc1Vu HbvsLDvvpqfwXcxb9rnLnAzhoZI1zweh9/rk7iJUQ5GUjiPEaF71bXNNIgRTvOgw n1p0vjHvCeP8pFAvUfgKq0/y9LKErZpWYQyJOGjR5INEhxsuOKgxND5rzBUgGXeS X/iuZe9qONbU+UMDqxm6e4K71Dbx41ie7ohCgQ= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:date:from:to:cc:subject:in-reply-to:message-id :references:mime-version:content-type; s=default; bh=HDhDY+a1vqC KKI0bHAbRfMUquZA=; b=BnIAv/H3Zin2kGigVYVN194UNktug8p4StrJbdxDsNE aPtx23HQUwOrhcfyvqn+3Ag+cwuabu3PnMPsFPM75m2Ny+DA9Fv/YSaBbYs3UYvn MgN/tN0qRpG/REg5RYd4OFxtpYIof0WZgpwEPQ7HaQJNkUzTbkyfRYnV3IEczKCs = Received: (qmail 26658 invoked by alias); 9 May 2019 15:46:17 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 26650 invoked by uid 89); 9 May 2019 15:46:17 -0000 Authentication-Results: sourceware.org; auth=none X-HELO: relay1.mentorg.com Date: Thu, 9 May 2019 15:46:01 +0000 From: Joseph Myers To: Lukasz Majewski CC: , Stepan Golosunov , Arnd Bergmann , Paul Eggert Subject: Re: [PATCH v2 2/7] y2038: Introduce __ASSUME_64BIT_TIME define In-Reply-To: <20190508121840.39aaedcb@jawa> Message-ID: References: <20190414220841.20243-1-lukma@denx.de> <20190429104613.16209-1-lukma@denx.de> <20190429104613.16209-3-lukma@denx.de> <20190430110505.2a0c7d1a@jawa> <20190506165510.7a6c20d1@jawa> <20190508121840.39aaedcb@jawa> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" On Wed, 8 May 2019, Lukasz Majewski wrote: > The 64 bit versions of syscalls (like clock_settime64 or > clock_gettime64) are available since 5.1 kernel (as you posted already > the following patch: "Update syscall-names.list for Linux 5.1" . > > I've now only focused on clock_settime(64) to make the discussion more > concrete. The following will be relevant for use of clock_gettime64, but is not immediately relevant for clock_settime64: clock_gettime64 will complicate things because the present clock_gettime code uses the vDSO on some architectures. Is clock_gettime64 available in the vDSO in 5.1 on all architectures where clock_gettime is? If it is, with the same symbol version as used for existing vDSO symbols, or a different symbol version? If not in the vDSO, are there any performance implications from using a clock_gettime64 syscall in place of a clock_gettime call to the vDSO? (I think the code using the vDSO will automatically fall back to a corresponding syscall if the vDSO symbol isn't there, but answers to those questions will still be relevant for reviewing any patch for clock_gettime64 and understanding exactly what code paths it will use.) -- Joseph S. Myers joseph@codesourcery.com