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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 654F4CA9EA0 for ; Wed, 23 Oct 2019 01:14:33 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3095720679 for ; Wed, 23 Oct 2019 01:14:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LgJgNgR3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3095720679 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:50270 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iN5EO-00052q-9t for qemu-devel@archiver.kernel.org; Tue, 22 Oct 2019 21:14:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:40992) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iN5Db-0004Sb-9X for qemu-devel@nongnu.org; Tue, 22 Oct 2019 21:13:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iN5Da-0006J0-BW for qemu-devel@nongnu.org; Tue, 22 Oct 2019 21:13:43 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:54732 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iN5Da-0006Hg-8J for qemu-devel@nongnu.org; Tue, 22 Oct 2019 21:13:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1571793221; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=1O0uPkSjaiBSnewfPYGEvo+0gVJer3elYoUv0JUWjoQ=; b=LgJgNgR3PWGKhMjxDSDf82PsawsNNgVww2+11exborWXeWmIPxZa+fwtp51RsBKD0YS+or IKV5QR3DmzNH8204Wc0tMSeAzWwCzSeBpBvnxokad1/AS1E0j180R+o7u56yWmq19RMED/ bfgQZ35rQHGmXSvEIl1zRMnJSZR0Jpg= 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-107-AwoFuPObOEqByoLT-OASOA-1; Tue, 22 Oct 2019 21:13:37 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9E4541005500; Wed, 23 Oct 2019 01:13:36 +0000 (UTC) Received: from [10.3.117.0] (ovpn-117-0.phx2.redhat.com [10.3.117.0]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A96A860C57; Wed, 23 Oct 2019 01:13:35 +0000 (UTC) Subject: Re: [PATCH v13 01/12] util/cutils: Add qemu_strtotime_ps() To: Tao Xu , imammedo@redhat.com, ehabkost@redhat.com References: <20191020111125.27659-1-tao3.xu@intel.com> <20191020111125.27659-2-tao3.xu@intel.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: <7a0662f5-28e3-4bb8-0b20-669d34cf56a6@redhat.com> Date: Tue, 22 Oct 2019 20:13:35 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: <20191020111125.27659-2-tao3.xu@intel.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: AwoFuPObOEqByoLT-OASOA-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: jingqi.liu@intel.com, fan.du@intel.com, qemu-devel@nongnu.org, jonathan.cameron@huawei.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 10/20/19 6:11 AM, Tao Xu wrote: > To convert strings with time suffixes to numbers, support time unit are > "ps" for picosecond, "ns" for nanosecond, "us" for microsecond, "ms" > for millisecond or "s" for second. I haven't yet reviewed the patch itself, but my off-hand observation: picosecond is probably too narrow to ever be useful. POSIX interfaces=20 only go down to nanoseconds, and when you start adding in vmexit delay=20 times and such, we're lucky when we get anything better than microsecond=20 accuracies. Supporting just three sub-second suffixes instead of four=20 would slightly simplify the code, and not cost you any real precision. --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org