From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <dev-bounces@dpdk.org> Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id CBE89A00C4; Tue, 26 Jul 2022 11:26:53 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 7116E40DDD; Tue, 26 Jul 2022 11:26:53 +0200 (CEST) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by mails.dpdk.org (Postfix) with ESMTP id D237140695 for <dev@dpdk.org>; Tue, 26 Jul 2022 11:26:51 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1658827611; 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=Re68g+PAUFBKz1GQEJgu0OScY0HFOv8wbi+thrsOOMY=; b=G0rXrmMia1gKW6N5ws4wc5+rFfdn7vKQuJxvB00ZBcoJungIQmGfaew4o0WGY53R66de5/ gXhpj8Qa30ZCOAHfU5Hr11g88MpbPh6Prc5+wisbs+Wpf8B10g8R+BDpCuq7l/gabbWbUz paoRgA8d5gqL8xmN0Gx12MbK4PN92V8= 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-519-dVVtfMEdNWmd4xjtP6hdag-1; Tue, 26 Jul 2022 05:26:48 -0400 X-MC-Unique: dVVtfMEdNWmd4xjtP6hdag-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C7B623C00086; Tue, 26 Jul 2022 09:26:47 +0000 (UTC) Received: from [10.39.208.26] (unknown [10.39.208.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 281161121319; Tue, 26 Jul 2022 09:26:46 +0000 (UTC) Message-ID: <551fa8d0-9855-cd8f-7d5b-5118f3583b7e@redhat.com> Date: Tue, 26 Jul 2022 11:26:45 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH v3 4/4] vhost: stop using mempool for IOTLB cache To: David Marchand <david.marchand@redhat.com>, dev@dpdk.org Cc: Chenbo Xia <chenbo.xia@intel.com> References: <20220722135320.109269-1-david.marchand@redhat.com> <20220725203206.427083-1-david.marchand@redhat.com> <20220725203206.427083-5-david.marchand@redhat.com> From: Maxime Coquelin <maxime.coquelin@redhat.com> In-Reply-To: <20220725203206.427083-5-david.marchand@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=maxime.coquelin@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions <dev.dpdk.org> List-Unsubscribe: <https://mails.dpdk.org/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://mails.dpdk.org/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <https://mails.dpdk.org/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> Errors-To: dev-bounces@dpdk.org On 7/25/22 22:32, David Marchand wrote: > A mempool consumes 3 memzones (with the default ring mempool driver). > The default DPDK configuration allows RTE_MAX_MEMZONE (2560) memzones. > > Assuming there is no other memzones that means that we can have a > maximum of 853 mempools. > > In the vhost library, the IOTLB cache code so far was requesting a > mempool per vq, which means that at the maximum, the vhost library > could request mempools for 426 qps. > > This limit was recently reached on big systems with a lot of virtio > ports (and multiqueue in use). > > While the limit on mempool count could be something we fix at the DPDK > project level, there is no reason to use mempools for the IOTLB cache: > - the IOTLB cache entries do not need to be DMA-able and are only used > by the current process (in multiprocess context), > - getting/putting objects from/in the mempool is always associated with > some other locks, so some level of lock contention is already present, > > We can convert to a malloc'd pool with objects put in a free list > protected by a spinlock. > > Signed-off-by: David Marchand <david.marchand@redhat.com> > --- > lib/vhost/iotlb.c | 102 ++++++++++++++++++++++++++++------------------ > lib/vhost/iotlb.h | 1 + > lib/vhost/vhost.c | 2 +- > lib/vhost/vhost.h | 4 +- > 4 files changed, 67 insertions(+), 42 deletions(-) > Thanks for working on this, this is definitely not needed to use mempool for this. Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com> Maxime