From owner-freebsd-arch@freebsd.org Mon Sep 9 17:38:14 2019 Return-Path: Delivered-To: freebsd-arch@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 B27B6D989E for ; Mon, 9 Sep 2019 17:38:14 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from smtp.freebsd.org (smtp.freebsd.org [96.47.72.83]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 46RwP24M85z4HyG; Mon, 9 Sep 2019 17:38:14 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Received: from John-Baldwins-MacBook-Pro-4.local (unknown [IPv6:2601:648:8880:1e30:c42c:770f:27f8:4624]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) (Authenticated sender: jhb) by smtp.freebsd.org (Postfix) with ESMTPSA id E0839B3F9; Mon, 9 Sep 2019 17:38:13 +0000 (UTC) (envelope-from jhb@FreeBSD.org) Subject: Re: What value HZ? To: Warner Losh , Philip Paeps Cc: "freebsd-arch@freebsd.org" References: <201909060119.x861JWrG006910@repo.freebsd.org> <4917d7507b6ea6c360dccda261f53052aa085f2b.camel@freebsd.org> <5EE266EE-E650-48D8-9B0E-E674AD026470@freebsd.org> <3cb6429acc7e520932d2c906d1cac47540156355.camel@freebsd.org> <8F03EA29-0F3F-4321-9241-78F7C924FDE1@freebsd.org> <9BC03B61-F8B5-476C-AD34-9DEA5230BFCF@freebsd.org> From: John Baldwin Openpgp: preference=signencrypt Autocrypt: addr=jhb@FreeBSD.org; keydata= mQGiBETQ+XcRBADMFybiq69u+fJRy/0wzqTNS8jFfWaBTs5/OfcV7wWezVmf9sgwn8TW0Dk0 c9MBl0pz+H01dA2ZSGZ5fXlmFIsee1WEzqeJzpiwd/pejPgSzXB9ijbLHZ2/E0jhGBcVy5Yo /Tw5+U/+laeYKu2xb0XPvM0zMNls1ah5OnP9a6Ql6wCgupaoMySb7DXm2LHD1Z9jTsHcAQMD /1jzh2BoHriy/Q2s4KzzjVp/mQO5DSm2z14BvbQRcXU48oAosHA1u3Wrov6LfPY+0U1tG47X 1BGfnQH+rNAaH0livoSBQ0IPI/8WfIW7ub4qV6HYwWKVqkDkqwcpmGNDbz3gfaDht6nsie5Z pcuCcul4M9CW7Md6zzyvktjnbz61BADGDCopfZC4of0Z3Ka0u8Wik6UJOuqShBt1WcFS8ya1 oB4rc4tXfSHyMF63aPUBMxHR5DXeH+EO2edoSwViDMqWk1jTnYza51rbGY+pebLQOVOxAY7k do5Ordl3wklBPMVEPWoZ61SdbcjhHVwaC5zfiskcxj5wwXd2E9qYlBqRg7QeSm9obiBCYWxk d2luIDxqaGJARnJlZUJTRC5vcmc+iGAEExECACAFAkTQ+awCGwMGCwkIBwMCBBUCCAMEFgID AQIeAQIXgAAKCRBy3lIGd+N/BI6RAJ9S97fvbME+3hxzE3JUyUZ6vTewDACdE1stFuSfqMvM jomvZdYxIYyTUpC5Ag0ERND5ghAIAPwsO0B7BL+bz8sLlLoQktGxXwXQfS5cInvL17Dsgnr3 1AKa94j9EnXQyPEj7u0d+LmEe6CGEGDh1OcGFTMVrof2ZzkSy4+FkZwMKJpTiqeaShMh+Goj XlwIMDxyADYvBIg3eN5YdFKaPQpfgSqhT+7El7w+wSZZD8pPQuLAnie5iz9C8iKy4/cMSOrH YUK/tO+Nhw8Jjlw94Ik0T80iEhI2t+XBVjwdfjbq3HrJ0ehqdBwukyeJRYKmbn298KOFQVHO EVbHA4rF/37jzaMadK43FgJ0SAhPPF5l4l89z5oPu0b/+5e2inA3b8J3iGZxywjM+Csq1tqz hltEc7Q+E08AAwUIAL+15XH8bPbjNJdVyg2CMl10JNW2wWg2Q6qdljeaRqeR6zFus7EZTwtX sNzs5bP8y51PSUDJbeiy2RNCNKWFMndM22TZnk3GNG45nQd4OwYK0RZVrikalmJY5Q6m7Z16 4yrZgIXFdKj2t8F+x613/SJW1lIr9/bDp4U9tw0V1g3l2dFtD3p3ZrQ3hpoDtoK70ioIAjjH aIXIAcm3FGZFXy503DOA0KaTWwvOVdYCFLm3zWuSOmrX/GsEc7ovasOWwjPn878qVjbUKWwx Q4QkF4OhUV9zPtf9tDSAZ3x7QSwoKbCoRCZ/xbyTUPyQ1VvNy/mYrBcYlzHodsaqUDjHuW+I SQQYEQIACQUCRND5ggIbDAAKCRBy3lIGd+N/BCO8AJ9j1dWVQWxw/YdTbEyrRKOY8YZNwwCf afMAg8QvmOWnHx3wl8WslCaXaE8= Message-ID: Date: Mon, 9 Sep 2019 13:38:14 -0400 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 09 Sep 2019 17:38:14 -0000 On 9/6/19 9:46 PM, Warner Losh wrote: > I'm top posting here, since this thread from a recent commit gives the > context > > I'm proposing basically the following patch: > > diff --git a/sys/kern/subr_param.c b/sys/kern/subr_param.c > index c0025c07eed..bb92afb6449 100644 > --- a/sys/kern/subr_param.c > +++ b/sys/kern/subr_param.c > @@ -61,11 +61,7 @@ __FBSDID("$FreeBSD$"); > */ > > #ifndef HZ > -# if defined(__mips__) || defined(__arm__) || defined(__riscv) > -# define HZ 100 > -# else > -# define HZ 1000 > -# endif > +# define HZ 1000 > # ifndef HZ_VM > # define HZ_VM 100 > # endif > > Along with removing HZ from almost all the kernel config files in arm and > mips where it is already 1000. I'm agnostic about riscv, so would also be > open to just removing the first two clauses from the #if the diff shows me > removing. I think this sounds fine. On x86 we use hz=100 instead of 1000 in VMs via a runtime test. I suspect if anything we might want to take that same factor into account here. Thus, it makes sense for mips MALTA configs (most often run under qemu) to use 100, and/or to add a runtime test for qemu that switches from 1000 to 100. Similarly, for riscv we probably want to use 100 under qemu and spike, but 1000 on actual hardware via either kernel config options or runtime checks. -- John Baldwin