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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 D7DB5C43381 for ; Thu, 14 Mar 2019 16:43:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 948402087C for ; Thu, 14 Mar 2019 16:43:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727357AbfCNQnC (ORCPT ); Thu, 14 Mar 2019 12:43:02 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20643 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726157AbfCNQnB (ORCPT ); Thu, 14 Mar 2019 12:43:01 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 102F730EEF69; Thu, 14 Mar 2019 16:43:01 +0000 (UTC) Received: from [10.40.205.82] (unknown [10.40.205.82]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A62E963F65; Thu, 14 Mar 2019 16:42:40 +0000 (UTC) Subject: Re: [RFC][Patch v9 0/6] KVM: Guest Free Page Hinting To: "Michael S. Tsirkin" Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, pbonzini@redhat.com, lcapitulino@redhat.com, pagupta@redhat.com, wei.w.wang@intel.com, yang.zhang.wz@gmail.com, riel@surriel.com, david@redhat.com, dodgen@google.com, konrad.wilk@oracle.com, dhildenb@redhat.com, aarcange@redhat.com, alexander.duyck@gmail.com References: <20190306155048.12868-1-nitesh@redhat.com> <20190306110501-mutt-send-email-mst@kernel.org> <20190306130955-mutt-send-email-mst@kernel.org> From: Nitesh Narayan Lal Openpgp: preference=signencrypt 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: Date: Thu, 14 Mar 2019 12:42:36 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190306130955-mutt-send-email-mst@kernel.org> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="UJZzxOXyC1WwQkZTeFpxvN96n6ZaZqUO0" X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Thu, 14 Mar 2019 16:43:01 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --UJZzxOXyC1WwQkZTeFpxvN96n6ZaZqUO0 Content-Type: multipart/mixed; boundary="l761DRoW01BOGI65Mrp4bgD4xjullzymp"; protected-headers="v1" From: Nitesh Narayan Lal To: "Michael S. Tsirkin" Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, pbonzini@redhat.com, lcapitulino@redhat.com, pagupta@redhat.com, wei.w.wang@intel.com, yang.zhang.wz@gmail.com, riel@surriel.com, david@redhat.com, dodgen@google.com, konrad.wilk@oracle.com, dhildenb@redhat.com, aarcange@redhat.com, alexander.duyck@gmail.com Message-ID: Subject: Re: [RFC][Patch v9 0/6] KVM: Guest Free Page Hinting References: <20190306155048.12868-1-nitesh@redhat.com> <20190306110501-mutt-send-email-mst@kernel.org> <20190306130955-mutt-send-email-mst@kernel.org> In-Reply-To: <20190306130955-mutt-send-email-mst@kernel.org> --l761DRoW01BOGI65Mrp4bgD4xjullzymp Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Language: en-US On 3/6/19 1:12 PM, Michael S. Tsirkin wrote: > On Wed, Mar 06, 2019 at 01:07:50PM -0500, Nitesh Narayan Lal wrote: >> On 3/6/19 11:09 AM, Michael S. Tsirkin wrote: >>> On Wed, Mar 06, 2019 at 10:50:42AM -0500, Nitesh Narayan Lal wrote: >>>> The following patch-set proposes an efficient mechanism for handing = freed memory between the guest and the host. It enables the guests with n= o page cache to rapidly free and reclaims memory to and from the host res= pectively. >>>> >>>> Benefit: >>>> With this patch-series, in our test-case, executed on a single syste= m and single NUMA node with 15GB memory, we were able to successfully lau= nch 5 guests(each with 5 GB memory) when page hinting was enabled and 3 w= ithout it. (Detailed explanation of the test procedure is provided at the= bottom under Test - 1). >>>> >>>> Changelog in v9: >>>> * Guest free page hinting hook is now invoked after a page has been= merged in the buddy. >>>> * Free pages only with order FREE_PAGE_HINTING_MIN_ORDER(cur= rently defined as MAX_ORDER - 1) are captured. >>>> * Removed kthread which was earlier used to perform the scanning, i= solation & reporting of free pages. >>>> * Pages, captured in the per cpu array are sorted based on the zone= numbers. This is to avoid redundancy of acquiring zone locks. >>>> * Dynamically allocated space is used to hold the isolated g= uest free pages. >>>> * All the pages are reported asynchronously to the host via = virtio driver. >>>> * Pages are returned back to the guest buddy free list only = when the host response is received. >>>> >>>> Pending items: >>>> * Make sure that the guest free page hinting's current imple= mentation doesn't break hugepages or device assigned guests. >>>> * Follow up on VIRTIO_BALLOON_F_PAGE_POISON's device side support. = (It is currently missing) >>>> * Compare reporting free pages via vring with vhost. >>>> * Decide between MADV_DONTNEED and MADV_FREE. >>>> * Analyze overall performance impact due to guest free page hinting= =2E >>>> * Come up with proper/traceable error-message/logs. >>>> >>>> Tests: >>>> 1. Use-case - Number of guests we can launch >>>> >>>> NUMA Nodes =3D 1 with 15 GB memory >>>> Guest Memory =3D 5 GB >>>> Number of cores in guest =3D 1 >>>> Workload =3D test allocation program allocates 4GB memory, touches = it via memset and exits. >>>> Procedure =3D >>>> The first guest is launched and once its console is up, the test al= location program is executed with 4 GB memory request (Due to this the gu= est occupies almost 4-5 GB of memory in the host in a system without page= hinting). Once this program exits at that time another guest is launched= in the host and the same process is followed. We continue launching the = guests until a guest gets killed due to low memory condition in the host.= >>>> >>>> Results: >>>> Without hinting =3D 3 >>>> With hinting =3D 5 >>>> >>>> 2. Hackbench >>>> Guest Memory =3D 5 GB=20 >>>> Number of cores =3D 4 >>>> Number of tasks Time with Hinting Time without Hinting >>>> 4000 19.540 17.818 >>>> >>> How about memhog btw? >>> Alex reported: >>> >>> My testing up till now has consisted of setting up 4 8GB VMs on a sy= stem >>> with 32GB of memory and 4GB of swap. To stress the memory on the sys= tem I >>> would run "memhog 8G" sequentially on each of the guests and observe= how >>> long it took to complete the run. The observed behavior is that on t= he >>> systems with these patches applied in both the guest and on the host= I was >>> able to complete the test with a time of 5 to 7 seconds per guest. O= n a >>> system without these patches the time ranged from 7 to 49 seconds pe= r >>> guest. I am assuming the variability is due to time being spent writ= ing >>> pages out to disk in order to free up space for the guest. >>> >> Here are the results: >> >> Procedure: 3 Guests of size 5GB is launched on a single NUMA node with= >> total memory of 15GB and no swap. In each of the guest, memhog is run >> with 5GB. Post-execution of memhog, Host memory usage is monitored by >> using Free command. >> >> Without Hinting: >> =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 =C2=A0=C2= =A0=C2=A0 Time of execution=C2=A0=C2=A0=C2=A0 Host used memory >> Guest 1:=C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 45 seconds=C2=A0=C2=A0=C2= =A0 =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 5.4 GB >> Guest 2:=C2=A0=C2=A0 =C2=A0=C2=A0 =C2=A0 45 seconds=C2=A0=C2=A0=C2=A0 = =C2=A0=C2=A0 =C2=A0=C2=A0 =C2=A0 10 GB >> Guest 3:=C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 1=C2=A0 minute=C2=A0=C2=A0= =C2=A0 =C2=A0=C2=A0 =C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0=C2=A0 15 GB >> >> With Hinting: >> =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 =C2=A0 =C2=A0= Time of execution =C2=A0=C2=A0=C2=A0 Host used memory >> Guest 1:=C2=A0=C2=A0 =C2=A0=C2=A0 =C2=A0 49 seconds=C2=A0=C2=A0=C2=A0 = =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 2.4 GB >> Guest 2:=C2=A0=C2=A0 =C2=A0=C2=A0 =C2=A0 40 seconds=C2=A0=C2=A0=C2=A0 = =C2=A0=C2=A0 =C2=A0=C2=A0 =C2=A0 4.3 GB >> Guest 3:=C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 50 seconds=C2=A0=C2=A0=C2= =A0 =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 6.3 GB > OK so no improvement. OTOH Alex's patches cut time down to 5-7 seconds > which seems better. Want to try testing Alex's patches for comparison? > I realized that the last time I reported the memhog numbers, I didn't enable the swap due to which the actual benefits of the series were not shown. I have re-run the test by including some of the changes suggested by Alexander and David: =C2=A0=C2=A0=C2=A0 * Reduced the size of the per-cpu array to 32 and mini= mum hinting threshold to 16. =C2=A0=C2=A0=C2=A0 * Reported length of isolated pages along with start p= fn, instead of the order from the guest. =C2=A0=C2=A0=C2=A0 * Used the reported length to madvise the entire lengt= h of address instead of a single 4K page. =C2=A0=C2=A0=C2=A0 * Replaced MADV_DONTNEED with MADV_FREE. Setup for the test: NUMA node:1 Memory: 15GB Swap: 4GB Guest memory: 6GB Number of core: 1 Process: A guest is launched and memhog is run with 6GB. As its execution is over next guest is launched. Everytime memhog execution time is monitored.=C2=A0=C2=A0=C2=A0 Results: =C2=A0=C2=A0=C2=A0 Without Hinting: =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0 Time of execution =C2=A0=C2=A0=C2=A0 Guest1:=C2=A0=C2=A0=C2=A0 22s =C2=A0=C2=A0=C2=A0 Guest2:=C2=A0=C2=A0=C2=A0 24s =C2=A0=C2=A0=C2=A0 Guest3: 1m29s =C2=A0=C2=A0=C2=A0 With Hinting: =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0 Time of execution =C2=A0=C2=A0=C2=A0 Guest1:=C2=A0=C2=A0=C2=A0 24s =C2=A0=C2=A0=C2=A0 Guest2:=C2=A0=C2=A0=C2=A0 25s =C2=A0=C2=A0=C2=A0 Guest3:=C2=A0=C2=A0=C2=A0 28s When hinting is enabled swap space is not used until memhog with 6GB is ran in 6th guest. --=20 Regards Nitesh --l761DRoW01BOGI65Mrp4bgD4xjullzymp-- --UJZzxOXyC1WwQkZTeFpxvN96n6ZaZqUO0 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEkXcoRVGaqvbHPuAGo4ZA3AYyozkFAlyKhHwACgkQo4ZA3AYy ozlEoA//VwKzRN/OZmcnzMr5uXBWcy9XTpTsnA8QUUhhEr9bIXbQkfdC/lzlhqD8 cs36Y2qqwKGkf0m8x1lHzOPppPLKUP3yM9V+cgzYDKb9gEAn+QxwcprnJ+5xvSeW NUdObFJ3PpOSFTpD6zE1aAGd68MsoYJvz0WLkSJyMOKe8TImvmkjRM/jk8Kp5Spb B0p1YxWZ7NY3cGynnz5f5vMapQAq68P9oxAAhYHuSovQ+P+Zc2iBO046JUNiex5o eM5A8fRsimsvNweCsJGmcAjYzP/xGj7VUP+x1/QIvrJqeVlyg1F971XaxnFy4ZLd uOBhSkCILSV2AOn4LfpAR5BGTkPwEa9kPZmbMzyehv12B9vO6j1SZRIVTgtQUfA2 b+Bh+2Z/MQRmDPzei0XZZ7awq+LFy4txib8SBtetpUu7CkmOpN5d8A88R0BRlDDc Wi0xJXJlvFQtYkTB51mSMAG/Jy4v+Nw8jDQ2zAW24utxZWpHeh+emveoOeMpc4+X Zl1C+kFwHNieLlubj5XTEGGhs71ttNDCsTwFPBou4Zg1wLGkUuPszSMmsThK7AQR Tj5/6w9QS9K8eGpqO/nERE8Ia9k6GxGaCQP1HKhlb1RFyBERbMfhof8KpXUAWdBi j8kTOpT+nkfrPC0FcPRwsPa5Er2e3McKkutXqWXVLWPVFuRh1MM= =K55Q -----END PGP SIGNATURE----- --UJZzxOXyC1WwQkZTeFpxvN96n6ZaZqUO0--