From 45bb7fb21c8d18294a9f92da99d01ab3c67c7df2 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Daniel=20P=2E=20Berrang=C3=A9?= Date: Tue, 10 Jun 2025 13:36:43 +0100 Subject: [PATCH] chardev/char-pty: skip automatic zero-init of large array MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The 'pty_chr_read' method has a 4k byte array used for copying data between the PTY 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 off the PTY. Signed-off-by: Daniel P. Berrangé Reviewed-by: Stefan Hajnoczi Message-id: 20250610123709.835102-6-berrange@redhat.com Signed-off-by: Stefan Hajnoczi --- chardev/char-pty.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/chardev/char-pty.c b/chardev/char-pty.c index c28554e6e0..674e9b3f14 100644 --- a/chardev/char-pty.c +++ b/chardev/char-pty.c @@ -154,7 +154,7 @@ static gboolean pty_chr_read(QIOChannel *chan, GIOCondition cond, void *opaque) Chardev *chr = CHARDEV(opaque); PtyChardev *s = PTY_CHARDEV(opaque); gsize len; - uint8_t buf[CHR_READ_BUF_LEN]; + QEMU_UNINITIALIZED uint8_t buf[CHR_READ_BUF_LEN]; ssize_t ret; len = sizeof(buf); -- 2.39.5