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| author | Daniel P. Berrangé <berrange@redhat.com> | 2025-06-10 13:36:59 +0100 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2025-06-12 13:40:16 -0400 |
| commit | 21cf31c51a7aeff4270c9b30b37e019c536d54b2 (patch) | |
| tree | 8c8c13d9237f400f434beaabc7e6a9f211bfb31f | |
| parent | e1afd5ee6eb2954f4baf3c97820e4aaf7de97d2a (diff) | |
| download | qemu-21cf31c51a7aeff4270c9b30b37e019c536d54b2.zip qemu-21cf31c51a7aeff4270c9b30b37e019c536d54b2.tar.gz qemu-21cf31c51a7aeff4270c9b30b37e019c536d54b2.tar.bz2 | |
hw/net/virtio-net: skip automatic zero-init of large arrays
The 'virtio_net_receive_rcu' method has three arrays with
VIRTQUEUE_MAX_SIZE elements, which are apprixmately 32k in
size used for copying data between guest and host. Skip the
automatic zero-init of these arrays to eliminate the
performance overhead in the I/O hot path.
The three arrays will be selectively initialized as required
when processing network buffers.
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20250610123709.835102-22-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
| -rw-r--r-- | hw/net/virtio-net.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index 221252e..eb93607 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -1911,9 +1911,9 @@ static ssize_t virtio_net_receive_rcu(NetClientState *nc, const uint8_t *buf, VirtIONet *n = qemu_get_nic_opaque(nc); VirtIONetQueue *q; VirtIODevice *vdev = VIRTIO_DEVICE(n); - VirtQueueElement *elems[VIRTQUEUE_MAX_SIZE]; - size_t lens[VIRTQUEUE_MAX_SIZE]; - struct iovec mhdr_sg[VIRTQUEUE_MAX_SIZE]; + QEMU_UNINITIALIZED VirtQueueElement *elems[VIRTQUEUE_MAX_SIZE]; + QEMU_UNINITIALIZED size_t lens[VIRTQUEUE_MAX_SIZE]; + QEMU_UNINITIALIZED struct iovec mhdr_sg[VIRTQUEUE_MAX_SIZE]; struct virtio_net_hdr_v1_hash extra_hdr; unsigned mhdr_cnt = 0; size_t offset, i, guest_offset, j; |