From owner-freebsd-net@freebsd.org Wed Oct 21 19:21:42 2020 Return-Path: Delivered-To: freebsd-net@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id ABB8642B58E for ; Wed, 21 Oct 2020 19:21:42 +0000 (UTC) (envelope-from rysto32@gmail.com) Received: from mail-ed1-x532.google.com (mail-ed1-x532.google.com [IPv6:2a00:1450:4864:20::532]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4CGgN54Gh3z4fr7 for ; Wed, 21 Oct 2020 19:21:41 +0000 (UTC) (envelope-from rysto32@gmail.com) Received: by mail-ed1-x532.google.com with SMTP id p13so3705052edi.7 for ; Wed, 21 Oct 2020 12:21:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=14FI7ktGa4Q1Wb+/e9bu57LW7Pc5Dqav2ZFbjqE1tEk=; b=reWqxJTy0ptR62OU0qXmi48LG/HPTJhTL6ZNjetK6HbPuAZ/1b+wj2XqD/2vhUbjfV 2PbgDzlDU62yObG2jLSHBo8jru16BKnrvBGNppxFtNiBEKd3Sj3WORkwh1X7Ihmy0gbv q4cxarX6MgRm4Uoy5Cl6RNLEY576C7sNyjfy5kw083gcojquJ6zGVrdWrZGuMAG1zdk3 nIaMFkcz2v24/RwEpbM7twhOyjG6YVfF/qFUrvflLYvu9jDK/wQNbsEAm8EaphHirMx2 N7q35Oi4xI5esruHRbMLXsfSMtnve7cUmffOsp8dhGEaLoeQqspFeWT4S1fl+mBJvft8 QQNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=14FI7ktGa4Q1Wb+/e9bu57LW7Pc5Dqav2ZFbjqE1tEk=; b=Aa+o1H9JfJnrfWPqouw0W863ll3vpfGnrvDanjOumHaFWdAK5PD8WS1jnagE4wTqOB Ds0QEAAb9d37VfvSU7hW3LWeMuB/zOpkKScd/LIt/mRcb5UPNiRqa+Tes7isV/mMr2Zx 7kuoGrcStyPbvYyNc4Ga22r4i2xCOcipVbT2WnyOaC7byCWEPjui1UBjSdJSamoItZa0 TR8dAnW7/kmyrL+tJq7qf8fIWDUpmgZ+0iHu7kQRm3mCjL4ySkdgWU/htGLnnKUmDcq5 w7YN3m9lw0jPytLdJ5ATrDsbHa/ufw18wDdN6klAkAF9kO7QpLqqgiDDErzF/PhCuXsl gYqg== X-Gm-Message-State: AOAM531zS9c6hksaA6DLknWkBPBi77PPKEXCS8pQhySsaSwkEuQBTLZu TWkCv7458hm21FZv7EvtTFvImsLn1iaBQcBX6L4= X-Google-Smtp-Source: ABdhPJwdk9EsHeaEqILHpaDPax3nMDkE7LAnIGON6i0jFVY0+HujMnltCQ0p50fQQLgM/8w8x5K1Fpa2//7AYR8C6oY= X-Received: by 2002:a50:ef0a:: with SMTP id m10mr4636587eds.116.1603308099167; Wed, 21 Oct 2020 12:21:39 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Ryan Stone Date: Wed, 21 Oct 2020 15:21:28 -0400 Message-ID: Subject: Re: safe_pause_us() is always at least 1 millisecond long To: =?UTF-8?Q?Mi=C5=82osz_Kaniewski?= Cc: freebsd-net Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 4CGgN54Gh3z4fr7 X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=gmail.com header.s=20161025 header.b=reWqxJTy; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (mx1.freebsd.org: domain of rysto32@gmail.com designates 2a00:1450:4864:20::532 as permitted sender) smtp.mailfrom=rysto32@gmail.com X-Spamd-Result: default: False [-3.94 / 15.00]; FREEMAIL_FROM(0.00)[gmail.com]; R_SPF_ALLOW(-0.20)[+ip6:2a00:1450:4000::/36]; TO_DN_ALL(0.00)[]; DKIM_TRACE(0.00)[gmail.com:+]; RCPT_COUNT_TWO(0.00)[2]; DMARC_POLICY_ALLOW(-0.50)[gmail.com,none]; NEURAL_HAM_SHORT(-0.93)[-0.926]; FREEMAIL_TO(0.00)[gmail.com]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVFROM(0.00)[gmail.com]; ASN(0.00)[asn:15169, ipnet:2a00:1450::/32, country:US]; DWL_DNSWL_NONE(0.00)[gmail.com:dkim]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.02)[-1.017]; R_DKIM_ALLOW(-0.20)[gmail.com:s=20161025]; FROM_HAS_DN(0.00)[]; NEURAL_HAM_LONG(-1.00)[-0.997]; TAGGED_RCPT(0.00)[]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-net@freebsd.org]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCVD_IN_DNSWL_NONE(0.00)[2a00:1450:4864:20::532:from]; RCVD_COUNT_TWO(0.00)[2]; RCVD_TLS_ALL(0.00)[]; MAILMAN_DEST(0.00)[freebsd-net] X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 21 Oct 2020 19:21:42 -0000 Using min is definitely not correct. That would ensure that you either got a pause of 1 tick or 0 ticks. This may get you better granularity, depending on the system. pause_sbt("e1000_delay", x * SBT_1US, x < 1000 ? 100 * SBT_1US : SBT_1MS, 0);