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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 73DA1C4727D for ; Tue, 22 Sep 2020 21:15:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 24CEB20715 for ; Tue, 22 Sep 2020 21:15:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="cqldDxe8" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726757AbgIVVPm (ORCPT ); Tue, 22 Sep 2020 17:15:42 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:47288 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726614AbgIVVPl (ORCPT ); Tue, 22 Sep 2020 17:15:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600809339; 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: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=FCeiV6ln0rHsHV1M+bIrXLkKRFukeRr/+utdmm7upbY=; b=cqldDxe8q5X2j9uLXlrtM/32lfi/JnP0CIoAlOYhKZSSzdZ8l/QZXloFDT4gg3YJUJQ/rh QQonF9+WleK0Dlf3QXc47M/HDgRo86/oBv50mI6JKqGApz99rkDTNDrMfMeB05cX8/fefy seLIeXEaZEEsADJE+r1TX3OSgRqQVmo= 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-159-a9caZSIMO2G-_FgdeKTWlg-1; Tue, 22 Sep 2020 17:15:35 -0400 X-MC-Unique: a9caZSIMO2G-_FgdeKTWlg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4AADE8030B8; Tue, 22 Sep 2020 21:15:33 +0000 (UTC) Received: from [10.10.115.78] (ovpn-115-78.rdu2.redhat.com [10.10.115.78]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 29FCA5C1A3; Tue, 22 Sep 2020 21:15:31 +0000 (UTC) Subject: Re: [RFC][Patch v1 1/3] sched/isolation: API to get num of hosekeeping CPUs To: Frederic Weisbecker Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-pci@vger.kernel.org, mtosatti@redhat.com, sassmann@redhat.com, jeffrey.t.kirsher@intel.com, jacob.e.keller@intel.com, jlelli@redhat.com, hch@infradead.org, bhelgaas@google.com, mike.marciniszyn@intel.com, dennis.dalessandro@intel.com, thomas.lendacky@amd.com, jerinj@marvell.com, mathias.nyman@intel.com, jiri@nvidia.com References: <20200909150818.313699-1-nitesh@redhat.com> <20200909150818.313699-2-nitesh@redhat.com> <20200921234044.GA31047@lenoir> <20200922100817.GB5217@lenoir> <20200922205805.GD5217@lenoir> From: Nitesh Narayan Lal Autocrypt: addr=nitesh@redhat.com; prefer-encrypt=mutual; keydata= mQINBFl4pQoBEADT/nXR2JOfsCjDgYmE2qonSGjkM1g8S6p9UWD+bf7YEAYYYzZsLtbilFTe z4nL4AV6VJmC7dBIlTi3Mj2eymD/2dkKP6UXlliWkq67feVg1KG+4UIp89lFW7v5Y8Muw3Fm uQbFvxyhN8n3tmhRe+ScWsndSBDxYOZgkbCSIfNPdZrHcnOLfA7xMJZeRCjqUpwhIjxQdFA7 n0s0KZ2cHIsemtBM8b2WXSQG9CjqAJHVkDhrBWKThDRF7k80oiJdEQlTEiVhaEDURXq+2XmG jpCnvRQDb28EJSsQlNEAzwzHMeplddfB0vCg9fRk/kOBMDBtGsTvNT9OYUZD+7jaf0gvBvBB lbKmmMMX7uJB+ejY7bnw6ePNrVPErWyfHzR5WYrIFUtgoR3LigKnw5apzc7UIV9G8uiIcZEn C+QJCK43jgnkPcSmwVPztcrkbC84g1K5v2Dxh9amXKLBA1/i+CAY8JWMTepsFohIFMXNLj+B RJoOcR4HGYXZ6CAJa3Glu3mCmYqHTOKwezJTAvmsCLd3W7WxOGF8BbBjVaPjcZfavOvkin0u DaFvhAmrzN6lL0msY17JCZo046z8oAqkyvEflFbC0S1R/POzehKrzQ1RFRD3/YzzlhmIowkM BpTqNBeHEzQAlIhQuyu1ugmQtfsYYq6FPmWMRfFPes/4JUU/PQARAQABtCVOaXRlc2ggTmFy YXlhbiBMYWwgPG5pbGFsQHJlZGhhdC5jb20+iQI9BBMBCAAnBQJZeKUKAhsjBQkJZgGABQsJ CAcCBhUICQoLAgQWAgMBAh4BAheAAAoJEKOGQNwGMqM56lEP/A2KMs/pu0URcVk/kqVwcBhU SnvB8DP3lDWDnmVrAkFEOnPX7GTbactQ41wF/xwjwmEmTzLrMRZpkqz2y9mV0hWHjqoXbOCS 6RwK3ri5e2ThIPoGxFLt6TrMHgCRwm8YuOSJ97o+uohCTN8pmQ86KMUrDNwMqRkeTRW9wWIQ EdDqW44VwelnyPwcmWHBNNb1Kd8j3xKlHtnS45vc6WuoKxYRBTQOwI/5uFpDZtZ1a5kq9Ak/ MOPDDZpd84rqd+IvgMw5z4a5QlkvOTpScD21G3gjmtTEtyfahltyDK/5i8IaQC3YiXJCrqxE r7/4JMZeOYiKpE9iZMtS90t4wBgbVTqAGH1nE/ifZVAUcCtycD0f3egX9CHe45Ad4fsF3edQ ESa5tZAogiA4Hc/yQpnnf43a3aQ67XPOJXxS0Qptzu4vfF9h7kTKYWSrVesOU3QKYbjEAf95 NewF9FhAlYqYrwIwnuAZ8TdXVDYt7Z3z506//sf6zoRwYIDA8RDqFGRuPMXUsoUnf/KKPrtR ceLcSUP/JCNiYbf1/QtW8S6Ca/4qJFXQHp0knqJPGmwuFHsarSdpvZQ9qpxD3FnuPyo64S2N Dfq8TAeifNp2pAmPY2PAHQ3nOmKgMG8Gn5QiORvMUGzSz8Lo31LW58NdBKbh6bci5+t/HE0H pnyVf5xhNC/FuQINBFl4pQoBEACr+MgxWHUP76oNNYjRiNDhaIVtnPRqxiZ9v4H5FPxJy9UD Bqr54rifr1E+K+yYNPt/Po43vVL2cAyfyI/LVLlhiY4yH6T1n+Di/hSkkviCaf13gczuvgz4 KVYLwojU8+naJUsiCJw01MjO3pg9GQ+47HgsnRjCdNmmHiUQqksMIfd8k3reO9SUNlEmDDNB XuSzkHjE5y/R/6p8uXaVpiKPfHoULjNRWaFc3d2JGmxJpBdpYnajoz61m7XJlgwl/B5Ql/6B dHGaX3VHxOZsfRfugwYF9CkrPbyO5PK7yJ5vaiWre7aQ9bmCtXAomvF1q3/qRwZp77k6i9R3 tWfXjZDOQokw0u6d6DYJ0Vkfcwheg2i/Mf/epQl7Pf846G3PgSnyVK6cRwerBl5a68w7xqVU 4KgAh0DePjtDcbcXsKRT9D63cfyfrNE+ea4i0SVik6+N4nAj1HbzWHTk2KIxTsJXypibOKFX 2VykltxutR1sUfZBYMkfU4PogE7NjVEU7KtuCOSAkYzIWrZNEQrxYkxHLJsWruhSYNRsqVBy KvY6JAsq/i5yhVd5JKKU8wIOgSwC9P6mXYRgwPyfg15GZpnw+Fpey4bCDkT5fMOaCcS+vSU1 UaFmC4Ogzpe2BW2DOaPU5Ik99zUFNn6cRmOOXArrryjFlLT5oSOe4IposgWzdwARAQABiQIl BBgBCAAPBQJZeKUKAhsMBQkJZgGAAAoJEKOGQNwGMqM5ELoP/jj9d9gF1Al4+9bngUlYohYu 0sxyZo9IZ7Yb7cHuJzOMqfgoP4tydP4QCuyd9Q2OHHL5AL4VFNb8SvqAxxYSPuDJTI3JZwI7 d8JTPKwpulMSUaJE8ZH9n8A/+sdC3CAD4QafVBcCcbFe1jifHmQRdDrvHV9Es14QVAOTZhnJ vweENyHEIxkpLsyUUDuVypIo6y/Cws+EBCWt27BJi9GH/EOTB0wb+2ghCs/i3h8a+bi+bS7L FCCm/AxIqxRurh2UySn0P/2+2eZvneJ1/uTgfxnjeSlwQJ1BWzMAdAHQO1/lnbyZgEZEtUZJ x9d9ASekTtJjBMKJXAw7GbB2dAA/QmbA+Q+Xuamzm/1imigz6L6sOt2n/X/SSc33w8RJUyor SvAIoG/zU2Y76pKTgbpQqMDmkmNYFMLcAukpvC4ki3Sf086TdMgkjqtnpTkEElMSFJC8npXv 3QnGGOIfFug/qs8z03DLPBz9VYS26jiiN7QIJVpeeEdN/LKnaz5LO+h5kNAyj44qdF2T2AiF HxnZnxO5JNP5uISQH3FjxxGxJkdJ8jKzZV7aT37sC+Rp0o3KNc+GXTR+GSVq87Xfuhx0LRST NK9ZhT0+qkiN7npFLtNtbzwqaqceq3XhafmCiw8xrtzCnlB/C4SiBr/93Ip4kihXJ0EuHSLn VujM7c/b4pps Organization: Red Hat Inc, Message-ID: <6e48babd-bcaf-dfc8-2126-2b6c146af0aa@redhat.com> Date: Tue, 22 Sep 2020 17:15:28 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200922205805.GD5217@lenoir> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=nitesh@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="QYzUDHNTb61HnSlFKTqgC3z0IwNPdzuvV" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --QYzUDHNTb61HnSlFKTqgC3z0IwNPdzuvV Content-Type: multipart/mixed; boundary="5tXC1a7iThP1XJYTIA1cJH8bOPBmCzdTQ" --5tXC1a7iThP1XJYTIA1cJH8bOPBmCzdTQ Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Language: en-US On 9/22/20 4:58 PM, Frederic Weisbecker wrote: > On Tue, Sep 22, 2020 at 09:50:55AM -0400, Nitesh Narayan Lal wrote: >> On 9/22/20 6:08 AM, Frederic Weisbecker wrote: >> TBH I don't have a very strong case here at the moment. >> But still, IMHO, this will force the user to have both managed irqs and >> nohz_full in their environments to avoid these kinds of issues. Is that = how >> we would like to proceed? > Yep that sounds good to me. I never know how much we want to split each a= nd any > of the isolation features but I'd rather stay cautious to separate HK_FLA= G_TICK > from the rest, just in case running in nohz_full mode ever becomes intere= sting > alone for performance and not just latency/isolation. Fair point. > > But look what you can do as well: > > diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c > index 5a6ea03f9882..9df9598a9e39 100644 > --- a/kernel/sched/isolation.c > +++ b/kernel/sched/isolation.c > @@ -141,7 +141,7 @@ static int __init housekeeping_nohz_full_setup(char *= str) > =09unsigned int flags; > =20 > =09flags =3D HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU | > -=09=09HK_FLAG_MISC | HK_FLAG_KTHREAD; > +=09=09HK_FLAG_MISC | HK_FLAG_KTHREAD | HK_FLAG_MANAGED_IRQ; > =20 > =09return housekeeping_setup(str, flags); > } > > > "nohz_full=3D" has historically gathered most wanted isolation features. = It can > as well isolate managed irqs. Nice, yeap this will work. > > >>> And then can we rename it to housekeeping_num_online()? >> It could be just me, but does something like hk_num_online_cpus() makes = more >> sense here? > Sure, that works as well. Thanks a lot for all the help. > > Thanks. > --=20 Nitesh --5tXC1a7iThP1XJYTIA1cJH8bOPBmCzdTQ-- --QYzUDHNTb61HnSlFKTqgC3z0IwNPdzuvV Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEkXcoRVGaqvbHPuAGo4ZA3AYyozkFAl9qaXAACgkQo4ZA3AYy ozmsIhAAhT1tTDjPDsnfQm5U2ZdjJGv7zbZ0MRpgKCalRL4pwiT3Yp1+7Z0FtgxD 1thqq21G8SdPOmXZq5AtHYU93JrWPqQIjbNV3y31QZBUhRc3WufMR2bOERBeXbwb +8FueM/dwVsiNX3wjhx05W+6Q+AmPxI9u28Aqs56FYLUgqm53fZsaNIu72FMJMuD 2NuCk5QQfWHqePWCxeZpZCmxL7k4OjHdG7FVebyVlllQyyKOiTgFWKOYn7xLkXjG dp0Ovn8b/q7x8wIRRQZos6L92M7weLzOxO2n0kcsaQDVcGh/LpOGotIWHRL6mDKK QE6v+HwpOO4YxgBMPGaNiJbjiSwOuqvnVLjPNZZaFa2+HZ5yQeX6tHHVS4s+e6eR rKNyQdhu3oZyvw3lI+oZmCa0dZeYwnGTqldv+555eNeDEPh6siE9d3vOBSXhCan9 3dRjo607Ew4/0prv+IzvGwWHN6fenxFPbSkLcgEK1SUiwFfY3yqGr23Yccxgb1Ro VvEU4Hs0nm5vpzH3gndLpxXqTTuFaDxrshFea+nzvTtisrkljwR29gwAzyqfxaWU KEXp+4PYImbepgV1+bPMSlsHb1QjsP1HS9+yiKgenMzOyNZ0H2zaZ/bTPf7mCVFU 0o5z2yYM1UkJ9WGCpMCEwKvv/z1+Z5eR40Bep1z/uHKwQyErpH0= =x6M0 -----END PGP SIGNATURE----- --QYzUDHNTb61HnSlFKTqgC3z0IwNPdzuvV--