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From: Stefan Hajnoczi <stefanha@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
	qemu-ppc@nongnu.org, "Paolo Bonzini" <pbonzini@redhat.com>,
	"Fam Zheng" <fam@euphon.net>,
	"Laurent Vivier" <laurent@vivier.eu>,
	"Hanna Reitz" <hreitz@redhat.com>,
	"Keith Busch" <kbusch@kernel.org>,
	"Steven Lee" <steven_lee@aspeedtech.com>,
	qemu-arm@nongnu.org, "Michael Tokarev" <mjt@tls.msk.ru>,
	qemu-block@nongnu.org, "Peter Maydell" <peter.maydell@linaro.org>,
	"Harsh Prateek Bora" <harshpb@linux.ibm.com>,
	"Marc-André Lureau" <marcandre.lureau@redhat.com>,
	"Frédéric Barrat" <fbarrat@linux.ibm.com>,
	"Rob Herring" <robh@kernel.org>,
	"Dmitry Fleytman" <dmitry.fleytman@gmail.com>,
	"Jamin Lin" <jamin_lin@aspeedtech.com>,
	qemu-s390x@nongnu.org, "Gerd Hoffmann" <kraxel@redhat.com>,
	"Halil Pasic" <pasic@linux.ibm.com>,
	"Kevin Wolf" <kwolf@redhat.com>,
	"Jason Wang" <jasowang@redhat.com>,
	"Cédric Le Goater" <clg@kaod.org>,
	"Klaus Jensen" <its@irrelevant.dk>,
	"Jeuk Kim" <jeuk20.kim@samsung.com>,
	"Edgar E. Iglesias" <edgar.iglesias@gmail.com>,
	"Daniel Henrique Barboza" <danielhb413@gmail.com>,
	"Stefan Hajnoczi" <stefanha@redhat.com>,
	"Nicholas Piggin" <npiggin@gmail.com>,
	"Christian Borntraeger" <borntraeger@linux.ibm.com>,
	"Andrew Jeffery" <andrew@codeconstruct.com.au>,
	"Jesper Devantier" <foss@defmacro.it>,
	qemu-trivial@nongnu.org, "Sven Schnelle" <svens@stackframe.org>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>,
	"Troy Lee" <leetroy@gmail.com>, "Joel Stanley" <joel@jms.id.au>,
	"Thomas Huth" <thuth@redhat.com>,
	"Hannes Reinecke" <hare@suse.com>,
	"Alistair Francis" <alistair@alistair23.me>,
	"Daniel P. Berrangé" <berrange@redhat.com>
Subject: [PULL v2 11/31] hw/audio/marvell_88w8618: skip automatic zero-init of large array
Date: Thu, 12 Jun 2025 13:48:55 -0400	[thread overview]
Message-ID: <20250612174855.238493-2-stefanha@redhat.com> (raw)
In-Reply-To: <20250612174855.238493-1-stefanha@redhat.com>

From: Daniel P. Berrangé <berrange@redhat.com>

The 'mv88w8618_audio_callback' 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 'buf' array will be fully initialized when reading data from
device memory.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20250610123709.835102-12-berrange@redhat.com
[Fixed hw/audio/gus in commit message --Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/audio/marvell_88w8618.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/audio/marvell_88w8618.c b/hw/audio/marvell_88w8618.c
index 6d3ebbb0c8..c5c79d083a 100644
--- a/hw/audio/marvell_88w8618.c
+++ b/hw/audio/marvell_88w8618.c
@@ -66,7 +66,7 @@ static void mv88w8618_audio_callback(void *opaque, int free_out, int free_in)
 {
     mv88w8618_audio_state *s = opaque;
     int16_t *codec_buffer;
-    int8_t buf[4096];
+    QEMU_UNINITIALIZED int8_t buf[4096];
     int8_t *mem_buffer;
     int pos, block_size;
 
-- 
2.49.0



  reply	other threads:[~2025-06-12 17:49 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-12 17:48 [PULL v2 00/31] Block patches Stefan Hajnoczi
2025-06-12 17:48 ` Stefan Hajnoczi [this message]
2025-06-17 13:11 ` Stefan Hajnoczi

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