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 Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3BB10C001B0 for ; Wed, 16 Aug 2023 12:30:42 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 6B8AC41F5F; Wed, 16 Aug 2023 12:30:41 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org 6B8AC41F5F Authentication-Results: smtp4.osuosl.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=JXvrtRbH X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id KE-xSg9OYKjt; Wed, 16 Aug 2023 12:30:40 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp4.osuosl.org (Postfix) with ESMTPS id BB97541F44; Wed, 16 Aug 2023 12:30:39 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org BB97541F44 Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 948D7C0071; Wed, 16 Aug 2023 12:30:39 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [IPv6:2605:bc80:3010::133]) by lists.linuxfoundation.org (Postfix) with ESMTP id D7A24C0032 for ; Wed, 16 Aug 2023 12:30:37 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id B2286403F8 for ; Wed, 16 Aug 2023 12:30:37 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org B2286403F8 Authentication-Results: smtp2.osuosl.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=JXvrtRbH X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id fms8NzdKzd0Y for ; Wed, 16 Aug 2023 12:30:37 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by smtp2.osuosl.org (Postfix) with ESMTPS id 064F9403E7 for ; Wed, 16 Aug 2023 12:30:36 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 064F9403E7 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1692189035; 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; bh=gJm0s/M+Kg1YF5GxLN6JBJXmw6ZG4JEwhaw6y9Y9T1I=; b=JXvrtRbHGTo3RArDCNGn0ZqYSp0QUGRrMNuLQ1+m4N3vbAH0moTboqC3jnCrlvYnHJg6Wj RF70vOO+wItVX65JRgH+tSXopuYIomA2lQQTLd5IbhM1ZS9E0Xxqt3jI8X1tBcnpo6CI9C S4Khhhk/OXYfyOsEV5wXxBvxw7yk190= Received: from mimecast-mx02.redhat.com (66.187.233.73 [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-654-S8WR71diNvaEOdM6fFO7yA-1; Wed, 16 Aug 2023 08:30:32 -0400 X-MC-Unique: S8WR71diNvaEOdM6fFO7yA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D07CD1C0691E; Wed, 16 Aug 2023 12:30:31 +0000 (UTC) Received: from localhost (unknown [10.39.193.154]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3943B40C207A; Wed, 16 Aug 2023 12:30:30 +0000 (UTC) Date: Wed, 16 Aug 2023 08:30:29 -0400 From: Stefan Hajnoczi To: Peter-Jan Gootzen Subject: Re: [PATCH V4] virtio-fs: Improved request latencies when Virtio queue is full Message-ID: <20230816123029.GA3425284@fedora> References: <20230703191457.1847740-1-peter-jan@gootzen.net> MIME-Version: 1.0 In-Reply-To: <20230703191457.1847740-1-peter-jan@gootzen.net> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 Cc: miklos@szeredi.hu, vgoyal@redhat.com, virtualization@lists.linux-foundation.org X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============3079266178494018503==" Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" --===============3079266178494018503== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="pKdks2p52MVefYqy" Content-Disposition: inline --pKdks2p52MVefYqy Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jul 03, 2023 at 09:14:59PM +0200, Peter-Jan Gootzen wrote: > When the Virtio queue is full, a work item is scheduled > to execute in 1ms that retries adding the request to the queue. > This is a large amount of time on the scale on which a > virtio-fs device can operate. When using a DPU this is around > 40us baseline without going to a remote server (4k, QD=3D1). > This patch queues requests when the Virtio queue is full, > and when a completed request is taken off, immediately fills > it back up with queued requests. >=20 > This reduces the 99.9th percentile latencies in our tests by > 60x and slightly increases the overall throughput, when using a > queue depth 2x the size of the Virtio queue size, with a > DPU-powered virtio-fs device. >=20 > Signed-off-by: Peter-Jan Gootzen > --- > V4: Removed return value on error changes to simplify patch, > that should be changed in another patch. > V3: Fixed requests falling into the void when -ENOMEM and no new > incoming requests. Virtio-fs now always lets -ENOMEM bubble up to > userspace. Also made queue full condition more explicit with > -ENOSPC in `send_forget_request`. > V2: Not scheduling dispatch work anymore when not needed > and changed delayed_work structs to work_struct structs >=20 > fs/fuse/virtio_fs.c | 32 +++++++++++++++++--------------- > 1 file changed, 17 insertions(+), 15 deletions(-) Reviewed-by: Stefan Hajnoczi --pKdks2p52MVefYqy Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAmTcwWUACgkQnKSrs4Gr c8gwmggAjDDSTmwhKnH2Z5UFrC2kTCpUhEKeRg6A/OP9yr9Tp93ibbzd3xLqj+pD kmCM/K3326pROSsEHF9NfQlPgr9VlABkYuxYhXu6Gdcba/LWsd9awyQNcwsutyjF rc5e7N7/rpHwoPrQ5Atk+XV3wphDGZR5ziDGaojXVu8TGNvr0RHrXSEks373g3ys U0FTFc5eFdIQwPllMrpB8lWfZNWNImvTfz7jskJuKzMV1LTr+1cIvr7nc9P04i+e Ffsu0B9yxwTBMrGJXZp1zp1cym0TLt78pvPOQbNm7XmLX1iJqiA0ddoNv8F1YWYM VSyRGaON4GUUjl9xbTYishlcWifypw== =SxuU -----END PGP SIGNATURE----- --pKdks2p52MVefYqy-- --===============3079266178494018503== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization --===============3079266178494018503==--