50 lines
1.9 KiB
Diff
50 lines
1.9 KiB
Diff
From 8b487658db35f371e4a527ed18a2ae63b4048f83 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= <berrange@redhat.com>
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Date: Tue, 10 Jun 2025 13:36:47 +0100
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Subject: [PATCH 10/31] hw/audio/es1370: skip automatic zero-init of large
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array
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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RH-Author: Stefan Hajnoczi <stefanha@redhat.com>
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RH-MergeRequest: 461: Solve -ftrivial-auto-var-init performance regression with QEMU_UNINITIALIZED
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RH-Jira: RHEL-99887
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RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
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RH-Commit: [9/30] d6be11e78b1af782f12d7a25fc6c297370aafd4a
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The 'es1370_transfer_audio' method has a 4k byte array used for
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copying data between the audio backend and device. Skip the automatic
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zero-init of this array to eliminate the performance overhead in
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the I/O hot path.
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The 'tmpbuf' array will be fully initialized when reading data from
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the audio backend and/or device memory.
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Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
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Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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Message-id: 20250610123709.835102-10-berrange@redhat.com
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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(cherry picked from commit 8236e206084b832d1d7ec947a4798b818f4cdf1f)
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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---
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hw/audio/es1370.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/hw/audio/es1370.c b/hw/audio/es1370.c
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index 4ab61d3b9d..6aea934f54 100644
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--- a/hw/audio/es1370.c
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+++ b/hw/audio/es1370.c
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@@ -604,7 +604,7 @@ static uint64_t es1370_read(void *opaque, hwaddr addr, unsigned size)
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static void es1370_transfer_audio (ES1370State *s, struct chan *d, int loop_sel,
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int max, bool *irq)
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{
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- uint8_t tmpbuf[4096];
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+ QEMU_UNINITIALIZED uint8_t tmpbuf[4096];
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size_t to_transfer;
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uint32_t addr = d->frame_addr;
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int sc = d->scount & 0xffff;
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--
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2.39.3
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