From nobody Tue Apr 7 17:39:37 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 468B5C4332F for ; Tue, 18 Oct 2022 04:06:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231149AbiJREGY (ORCPT ); Tue, 18 Oct 2022 00:06:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230427AbiJREF7 (ORCPT ); Tue, 18 Oct 2022 00:05:59 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1BD9692F66 for ; Mon, 17 Oct 2022 21:05:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1666065946; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/RCLmwcdRRHc5iUwT+6ibxZ6InHRbOkdgeEhTg+vaBw=; b=APHHVZ4yJk1zqsgx8iVh6G5dAcLXNJ9P26fqcpI2jPcPgsYUYaiDUh4BPYVkwlmol7RgcE G44v5Ig4pG7b6+XyyBciSXXgDH+llbcef1x9cHrSQ1iQZ+yXUb7NpbSbTx7BeLD1ei8akH hCAAHfnw/l8U6D+O6+ge1mGQAkqkJ4E= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-62-2lhYu8McORSGNCmBrHRyQw-1; Tue, 18 Oct 2022 00:05:42 -0400 X-MC-Unique: 2lhYu8McORSGNCmBrHRyQw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 36C663C3C968; Tue, 18 Oct 2022 04:05:42 +0000 (UTC) Received: from gshan.redhat.com (vpn2-54-70.bne.redhat.com [10.64.54.70]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0BF7C2166B41; Tue, 18 Oct 2022 04:05:36 +0000 (UTC) From: Gavin Shan To: kvmarm@lists.linux.dev Cc: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, ajones@ventanamicro.com, pbonzini@redhat.com, maz@kernel.org, shuah@kernel.org, oliver.upton@linux.dev, mail@maciej.szmigiero.name, maciej.szmigiero@oracle.com, seanjc@google.com, peterx@redhat.com, ricarkol@google.com, zhenyzha@redhat.com, shan.gavin@gmail.com Subject: [PATCH v2 6/6] KVM: selftests: memslot_perf_test: Report optimal memory slots Date: Tue, 18 Oct 2022 12:04:54 +0800 Message-Id: <20221018040454.405719-7-gshan@redhat.com> In-Reply-To: <20221018040454.405719-1-gshan@redhat.com> References: <20221018040454.405719-1-gshan@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The memory area in each slot should be aligned to host page size. Otherwise, the test will fail. For example, the following command fails with the following messages with 64KB-page-size-host and 4KB-pae-size-guest. It's not user friendly to abort the test. Lets do something to report the optimal memory slots, instead of failing the test. # ./memslot_perf_test -v -s 1000 Number of memory slots: 999 Testing map performance with 1 runs, 5 seconds each Adding slots 1..999, each slot with 8 pages + 216 extra pages last =3D=3D=3D=3D Test Assertion Failure =3D=3D=3D=3D lib/kvm_util.c:824: vm_adjust_num_guest_pages(vm->mode, npages) =3D=3D = npages pid=3D19872 tid=3D19872 errno=3D0 - Success 1 0x00000000004065b3: vm_userspace_mem_region_add at kvm_util.c:822 2 0x0000000000401d6b: prepare_vm at memslot_perf_test.c:273 3 (inlined by) test_execute at memslot_perf_test.c:756 4 (inlined by) test_loop at memslot_perf_test.c:994 5 (inlined by) main at memslot_perf_test.c:1073 6 0x0000ffff7ebb4383: ?? ??:0 7 0x00000000004021ff: _start at :? Number of guest pages is not compatible with the host. Try npages=3D16 Report the optimal memory slots instead of failing the test when the memory area in each slot isn't aligned to host page size. With this applied, the optimal memory slots is reported. # ./memslot_perf_test -v -s 1000 Number of memory slots: 999 Testing map performance with 1 runs, 5 seconds each Memslot count too high for this test, decrease the cap (max is 514) Signed-off-by: Gavin Shan --- .../testing/selftests/kvm/memslot_perf_test.c | 45 +++++++++++++++++-- 1 file changed, 41 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/kvm/memslot_perf_test.c b/tools/testin= g/selftests/kvm/memslot_perf_test.c index 3ab385e40bc0..e0f3d9bd5297 100644 --- a/tools/testing/selftests/kvm/memslot_perf_test.c +++ b/tools/testing/selftests/kvm/memslot_perf_test.c @@ -229,16 +229,52 @@ static struct vm_data *alloc_vm(void) return data; } =20 +static bool check_slot_pages(uint32_t host_page_size, uint32_t guest_page_= size, + uint64_t pages_per_slot, uint64_t rempages) +{ + if (!pages_per_slot) + return false; + + if ((pages_per_slot * guest_page_size) % host_page_size) + return false; + + if ((rempages * guest_page_size) % host_page_size) + return false; + + return true; +} + + +static uint64_t get_max_slots(struct vm_data *data, uint32_t host_page_siz= e) +{ + uint32_t guest_page_size =3D data->vm->page_size; + uint64_t mempages, pages_per_slot, rempages; + uint64_t slots; + + mempages =3D data->npages; + slots =3D data->nslots; + while (--slots > 1) { + pages_per_slot =3D mempages / slots; + rempages =3D mempages % pages_per_slot; + if (check_slot_pages(host_page_size, guest_page_size, + pages_per_slot, rempages)) + return slots + 1; /* slot 0 is reserved */ + } + + return 0; +} + static bool prepare_vm(struct vm_data *data, int nslots, uint64_t *maxslot= s, void *guest_code, uint64_t mem_size, struct timespec *slot_runtime) { uint64_t mempages, rempages; uint64_t guest_addr; - uint32_t slot, guest_page_size; + uint32_t slot, host_page_size, guest_page_size; struct timespec tstart; struct sync_area *sync; =20 + host_page_size =3D getpagesize(); guest_page_size =3D vm_guest_mode_params[VM_MODE_DEFAULT].page_size; mempages =3D mem_size / guest_page_size; =20 @@ -250,12 +286,13 @@ static bool prepare_vm(struct vm_data *data, int nslo= ts, uint64_t *maxslots, TEST_ASSERT(data->npages > 1, "Can't test without any memory"); data->nslots =3D nslots; data->pages_per_slot =3D data->npages / data->nslots; - if (!data->pages_per_slot) { - *maxslots =3D data->npages + 1; + rempages =3D data->npages % data->nslots; + if (!check_slot_pages(host_page_size, guest_page_size, + data->pages_per_slot, rempages)) { + *maxslots =3D get_max_slots(data, host_page_size); return false; } =20 - rempages =3D data->npages % data->nslots; data->hva_slots =3D malloc(sizeof(*data->hva_slots) * data->nslots); TEST_ASSERT(data->hva_slots, "malloc() fail"); =20 --=20 2.23.0