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chardev/char-fd: skip automatic zero-init of large array

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The 'fd_chr_read' method has a 4k byte array used for copying
data between the socket 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 network socket.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20250610123709.835102-5-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Daniel P. Berrangé 2025-06-10 13:36:42 +01:00 • committed by Stefan Hajnoczi
parent 83750c1da8
commit a503bdc22b
1 changed files with 1 additions and 1 deletions
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2
chardev/char-fd.c
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@ -50,7 +50,7 @@ static gboolean fd_chr_read(QIOChannel *chan, GIOCondition cond, void *opaque)
Chardev *chr = CHARDEV(opaque);
FDChardev *s = FD_CHARDEV(opaque);
int len;
uint8_t buf[CHR_READ_BUF_LEN];
QEMU_UNINITIALIZED uint8_t buf[CHR_READ_BUF_LEN];
ssize_t ret;
len = sizeof(buf);