From nobody Wed May 29 19:24:41 2024 X-Original-To: dev-commits-doc-all@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4VqK892grdz5L7jq for ; Wed, 29 May 2024 19:24:41 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (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 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4VqK8926X9z505N; Wed, 29 May 2024 19:24:41 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1717010681; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=8+81rSTPiJNlKFMUgNbjM8bVTqr+CI20TSSOEltfIbU=; b=VhenYiaIKCWZgp1Im3aiCa9wTx4HHxJYxnC6sXWyWlce/835sXvCFHPDibsAlRZScVExsL SZPEb+gDVpYJE2bFCJL/buek3kfGAMfQyiGAewdSuH1RQFMQo80R+YY2CzuwdMWPF5sYCT 1FOhcGGCKyvUhqs6/5mEYxO9tVecjvet+fYrR3l8RmC0Xiplwp+a37bg4Lqychk5crb5Eh 5Cnqrf+huLQqGU7aFUubFp7jOgMIDpl7EdioPdDqAxwnqQsRR7LVAWiDDanHs6DihI/wET z0JyPIHcnB+0KlySW0BQsw1RIKH/iLLtA79pbJUeYhVcUqyBooiGffNXd8y4Mw== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1717010681; a=rsa-sha256; cv=none; b=QYgkofWxvzOWBo4zHMOAhn6ggOc3HveARcrQbZChYv3zStudwDL0m3rHC61ZXitdpYLYd1 AZvPvwe8poq01FWat4gl3m8SwEAq2jyMkDzHjE6As3kqPtKwqU7rOUDWDOcUubkdBAjiuu VGGNbClUL5p1mPE0tFNWOaQ+jehzWpzJ2M8w9Og/8HdYk5d8Pxjke5anLCCl/FIe7MdazU Lj2shwq9FBb1kimVQ5qrrbp7Xya2+WuHzGgt7oDw7K9mkVrKNuQHEykJWoDblwiMzs30rH IO8dq9lWkZvmETT0j56n6AYos1d5fTDQ86mudjSsPFoaW84y7esTVUaZFvoXxQ== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1717010681; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=8+81rSTPiJNlKFMUgNbjM8bVTqr+CI20TSSOEltfIbU=; b=cKjP9MKBpWSopka+ZstiJLmVZ39LrqBDDWk20VXBS9xhuNxh8WIFfPCQoFgEo3HggOrf5j rSA8JcW7pQsR8e4TxWVjYHW/pTQEl9d+OYFzYX+tWriHw1M7GIyv3vCZ+byYwRDE6/DIUr R7ZtTIvDalGn6eAQVYwrJGO0XxFklTcTXWkKOuD6GcuW1xBBbwJQnZZFtmUd5wftICkR1D 2SgvONtx94TGrSTAYGtagskgUbT1cE5x1YLyO81gpckCa04gquZD/EYVZtHKkGZoKHSEIl +OHutBZdaf4YJbr9i2A7P2qTA1tnf9Vaj+tPu+KjjZXeZaAOok2hKxkfJvYT9Q== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (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) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4VqK891bhtz185b; Wed, 29 May 2024 19:24:41 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.17.1/8.17.1) with ESMTP id 44TJOftY088240; Wed, 29 May 2024 19:24:41 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.17.1/8.17.1/Submit) id 44TJOfdI088237; Wed, 29 May 2024 19:24:41 GMT (envelope-from git) Date: Wed, 29 May 2024 19:24:41 GMT Message-Id: <202405291924.44TJOfdI088237@gitrepo.freebsd.org> To: doc-committers@FreeBSD.org, dev-commits-doc-all@FreeBSD.org From: Benedict Reuschling Subject: git: fd25efa62a - main - Add bullet-point about disabling "Turbo-modes" List-Id: Commit messages for all branches of the doc repository List-Archive: https://lists.freebsd.org/archives/dev-commits-doc-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-doc-all@freebsd.org Sender: owner-dev-commits-doc-all@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: bcr X-Git-Repository: doc X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: fd25efa62a92d2abdeec0493fba2d30a68ce43db Auto-Submitted: auto-generated The branch main has been updated by bcr: URL: https://cgit.FreeBSD.org/doc/commit/?id=fd25efa62a92d2abdeec0493fba2d30a68ce43db commit fd25efa62a92d2abdeec0493fba2d30a68ce43db Author: Benedict Reuschling AuthorDate: 2024-05-29 19:21:31 +0000 Commit: Benedict Reuschling CommitDate: 2024-05-29 19:21:31 +0000 Add bullet-point about disabling "Turbo-modes" Elaborate on this point a bit how and why they interfere with microbenchmarking. PR: 262646 --- .../content/en/books/developers-handbook/testing/_index.adoc | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/documentation/content/en/books/developers-handbook/testing/_index.adoc b/documentation/content/en/books/developers-handbook/testing/_index.adoc index 4aae09a4ad..508268d60b 100644 --- a/documentation/content/en/books/developers-handbook/testing/_index.adoc +++ b/documentation/content/en/books/developers-handbook/testing/_index.adoc @@ -72,7 +72,9 @@ It is not possible to use all of the suggestions below every single time, but th * Remove all non-essential device drivers from the kernel. For instance if USB is not needed for the test, do not put USB in the kernel. Drivers which attach often have timeouts ticking away. * Unconfigure hardware that are not in use. Detach disks with man:atacontrol[8] and man:camcontrol[8] if the disks are not used for the test. * Do not configure the network unless it is being tested, or wait until after the test has been performed to ship the results off to another computer. -+ +* Disable "Turbo-modes" because they make the clock frequency explicitly depend on the environment. This means that benchmark runs on 100% identical + code, may depend on time of day, coffee vs. soda or even how many other people are in the office. + If the system must be connected to a public network, watch out for spikes of broadcast traffic. Even though it is hardly noticeable, it will take up CPU cycles. Multicast has similar caveats. * Put each file system on its own disk. This minimizes jitter from head-seek optimizations. * Minimize output to serial or VGA consoles. Running output into files gives less jitter. (Serial consoles easily become a bottleneck.) Do not touch keyboard while the test is running, even kbd:[space] or kbd:[back-space] shows up in the numbers.