From nobody Sat Nov 15 17:05:51 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=quarantine dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1749666626; cv=none; d=zohomail.com; s=zohoarc; b=Qc8dKw3gWxkNUSvnlIGO7AWCWLDnp3hzA3YXf8ecl8K91v1gcYlR1FewcQx/012MULx/Wu+RnVJqd99RJyzmz5aGft7kCraQTRigfr2pDLF10Gr9iwRqzHmhL4sS24x4IoFDN3yHgh1GKb376LP34YW4MV9RzU9gjgMUNBR6BDE= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1749666626; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=12JvcWeA/xERILlNpLG6k8ImP52Q27ruWL1INzcd1O0=; b=VUBkK8kRFjS2dwKghoJ5hk0wSY3gShN5Q0FqGknDBCax5eeSR2PZfUB9hkRJtnxeEbTWbcs+DxmlGIWxFR7sMZEIjbHfIf3MRD4LziDqPWMyHonAzyNFxV3DPbSKwZw2DkHPtxgdOuVD0lPmLPSz6G/PzFtK3T35CIDeZisaPL0= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=quarantine dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1749666626168725.2547674577194; Wed, 11 Jun 2025 11:30:26 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uPQB7-0003WA-JA; Wed, 11 Jun 2025 14:28:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uPQ9v-0001fF-US for qemu-devel@nongnu.org; Wed, 11 Jun 2025 14:26:48 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uPQ9n-0001OU-5I for qemu-devel@nongnu.org; Wed, 11 Jun 2025 14:26:47 -0400 Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-611-csKpKmkNMU6GEknqFbMg1w-1; Wed, 11 Jun 2025 14:26:34 -0400 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 013FE1956051; Wed, 11 Jun 2025 18:26:31 +0000 (UTC) Received: from localhost (unknown [10.2.16.122]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 9F58D19560A3; Wed, 11 Jun 2025 18:26:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1749666398; 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=12JvcWeA/xERILlNpLG6k8ImP52Q27ruWL1INzcd1O0=; b=AfwGGVgPXqgi5iVa3Lg2SakSTQYCulk54omh91LHBweXgXe+R2jFZv0wO+w6jswtFHxXeS dmqh7nra9TolgflgTN3D/l5DRAGxinu5QMjNm8imYW4CGK7qLJ40Adz2+H56ywb11IZqFB mVxo8okOpCR3qKyuIIS3hnZpI+pgIto= X-MC-Unique: csKpKmkNMU6GEknqFbMg1w-1 X-Mimecast-MFC-AGG-ID: csKpKmkNMU6GEknqFbMg1w_1749666391 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: qemu-ppc@nongnu.org, Daniel Henrique Barboza , qemu-block@nongnu.org, Jesper Devantier , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Peter Maydell , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Harsh Prateek Bora , Troy Lee , Paolo Bonzini , Hanna Reitz , qemu-s390x@nongnu.org, Halil Pasic , Kevin Wolf , "Michael S. Tsirkin" , qemu-trivial@nongnu.org, Dmitry Fleytman , Jason Wang , Keith Busch , Nicholas Piggin , =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Barrat?= , Fam Zheng , Sven Schnelle , Stefan Hajnoczi , Joel Stanley , Gerd Hoffmann , "Edgar E. Iglesias" , qemu-arm@nongnu.org, Hannes Reinecke , Klaus Jensen , Jeuk Kim , Andrew Jeffery , Alistair Francis , Thomas Huth , Michael Tokarev , Laurent Vivier , Rob Herring , Steven Lee , Jamin Lin , Christian Borntraeger , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Subject: [PULL 10/31] hw/audio/gus: skip automatic zero-init of large array Date: Wed, 11 Jun 2025 14:25:12 -0400 Message-ID: <20250611182533.200590-11-stefanha@redhat.com> In-Reply-To: <20250611182533.200590-1-stefanha@redhat.com> References: <20250611182533.200590-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1749666628493116600 From: Daniel P. Berrang=C3=A9 The 'GUS_read_DMA' method has a 4k byte array used for copying data between the audio backend and device. Skip the automatic zero-init of this array to eliminate the performance overhead in the I/O hot path. The 'tmpbuf' array will be fully initialized when reading data from device memory. Signed-off-by: Daniel P. Berrang=C3=A9 Reviewed-by: Stefan Hajnoczi Message-id: 20250610123709.835102-11-berrange@redhat.com Signed-off-by: Stefan Hajnoczi --- hw/audio/gus.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/audio/gus.c b/hw/audio/gus.c index 87e8634893..c36df0240f 100644 --- a/hw/audio/gus.c +++ b/hw/audio/gus.c @@ -183,7 +183,7 @@ static int GUS_read_DMA (void *opaque, int nchan, int d= ma_pos, int dma_len) { GUSState *s =3D opaque; IsaDmaClass *k =3D ISADMA_GET_CLASS(s->isa_dma); - char tmpbuf[4096]; + QEMU_UNINITIALIZED char tmpbuf[4096]; int pos =3D dma_pos, mode, left =3D dma_len - dma_pos; =20 ldebug ("read DMA %#x %d\n", dma_pos, dma_len); --=20 2.49.0