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From: "Daniel P. Berrangé" <berrange@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Philippe Mathieu-Daudé" <philmd@linaro.org>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	"Peter Maydell" <peter.maydell@linaro.org>,
	qemu-block@nongnu.org, "Stefan Hajnoczi" <stefanha@redhat.com>,
	"Kevin Wolf" <kwolf@redhat.com>,
	"Daniel P. Berrangé" <berrange@redhat.com>
Subject: [PATCH 16/31] hw/display/vmware_vga: skip automatic zero-init of large struct
Date: Tue, 10 Jun 2025 13:36:54 +0100	[thread overview]
Message-ID: <20250610123709.835102-17-berrange@redhat.com> (raw)
In-Reply-To: <20250610123709.835102-1-berrange@redhat.com>

The 'vmsvga_fifo_run' method has a struct which is a little over 20k
in size, used for holding image data for cursor changes. Skip the
automatic zero-init of this struct to eliminate the performance
overhead in the I/O hot path.

The cursor variable will be fully initialized only when processing
a cursor definition message from the guest.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 hw/display/vmware_vga.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/display/vmware_vga.c b/hw/display/vmware_vga.c
index 544bb65320..bc1a8ed466 100644
--- a/hw/display/vmware_vga.c
+++ b/hw/display/vmware_vga.c
@@ -618,7 +618,7 @@ static void vmsvga_fifo_run(struct vmsvga_state_s *s)
     uint32_t cmd, colour;
     int args, len, maxloop = 1024;
     int x, y, dx, dy, width, height;
-    struct vmsvga_cursor_definition_s cursor;
+    QEMU_UNINITIALIZED struct vmsvga_cursor_definition_s cursor;
     uint32_t cmd_start;
 
     len = vmsvga_fifo_length(s);
-- 
2.49.0



  parent reply	other threads:[~2025-06-10 12:39 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-10 12:36 [PATCH 00/31] Skip automatic zero-init of large arrays / structs in I/O paths Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 01/31] include/qemu/compiler: add QEMU_UNINITIALIZED attribute macro Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 02/31] hw/virtio/virtio: avoid cost of -ftrivial-auto-var-init in hot path Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 03/31] block: skip automatic zero-init of large array in ioq_submit Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 04/31] chardev/char-fd: skip automatic zero-init of large array Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 05/31] chardev/char-pty: " Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 06/31] chardev/char-socket: " Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 07/31] hw/audio/ac97: skip automatic zero-init of large arrays Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 08/31] hw/audio/cs4231a: " Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 09/31] hw/audio/es1370: skip automatic zero-init of large array Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 10/31] hw/audio/gus: " Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 11/31] " Daniel P. Berrangé
2025-06-10 14:23   ` Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 12/31] hw/audio/sb16: " Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 13/31] hw/audio/via-ac97: " Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 14/31] hw/char/sclpconsole-lm: " Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 15/31] hw/dma/xlnx_csu_dma: " Daniel P. Berrangé
2025-06-10 12:36 ` Daniel P. Berrangé [this message]
2025-06-10 12:36 ` [PATCH 17/31] hw/hyperv/syndbg: " Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 18/31] hw/misc/aspeed_hace: " Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 19/31] hw/net/rtl8139: " Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 20/31] hw/net/tulip: " Daniel P. Berrangé
2025-06-10 12:36 ` [PATCH 21/31] hw/net/virtio-net: skip automatic zero-init of large arrays Daniel P. Berrangé
2025-06-10 12:37 ` [PATCH 22/31] hw/net/xgamc: skip automatic zero-init of large array Daniel P. Berrangé
2025-06-10 12:37 ` [PATCH 23/31] hw/nvme/ctrl: skip automatic zero-init of large arrays Daniel P. Berrangé
2025-06-11  8:55   ` Klaus Jensen
2025-06-10 12:37 ` [PATCH 24/31] hw/ppc/pnv_occ: skip automatic zero-init of large struct Daniel P. Berrangé
2025-06-11  9:09   ` Harsh Prateek Bora
2025-06-10 12:37 ` [PATCH 25/31] hw/ppc/spapr_tpm_proxy: skip automatic zero-init of large arrays Daniel P. Berrangé
2025-06-11  9:20   ` Harsh Prateek Bora
2025-06-10 12:37 ` [PATCH 26/31] hw/usb/hcd-ohci: skip automatic zero-init of large array Daniel P. Berrangé
2025-06-10 12:37 ` [PATCH 27/31] hw/scsi/lsi53c895a: " Daniel P. Berrangé
2025-06-10 12:37 ` [PATCH 28/31] hw/scsi/megasas: skip automatic zero-init of large arrays Daniel P. Berrangé
2025-06-10 12:37 ` [PATCH 29/31] hw/ufs/lu: skip automatic zero-init of large array Daniel P. Berrangé
2025-06-10 12:37 ` [PATCH 30/31] net/socket: " Daniel P. Berrangé
2025-06-10 12:37 ` [PATCH 31/31] net/stream: " Daniel P. Berrangé
2025-06-10 12:49 ` [PATCH 00/31] Skip automatic zero-init of large arrays / structs in I/O paths Philippe Mathieu-Daudé
2025-06-10 12:56   ` Daniel P. Berrangé
2025-06-10 15:00     ` Philippe Mathieu-Daudé
2025-06-10 15:56       ` Daniel P. Berrangé
2025-06-10 14:04 ` Stefan Hajnoczi
2025-06-11 19:19 ` Stefan Hajnoczi

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