migration: use a single I/O operation when writev_buffer is not defined
The recent patches to use vectored I/O for RAM migration caused a regression in savevm speed. To restore previous performance, add data to the buffer in qemu_put_buffer_async whenever writev_buffer is not available in the QEMUFile. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is contained in:
parent
af74db72d3
commit
7ce51f1b81
49
savevm.c
49
savevm.c
@ -525,27 +525,24 @@ static void qemu_file_set_error(QEMUFile *f, int ret)
|
||||
static void qemu_fflush(QEMUFile *f)
|
||||
{
|
||||
ssize_t ret = 0;
|
||||
int i = 0;
|
||||
|
||||
if (!f->ops->writev_buffer && !f->ops->put_buffer) {
|
||||
return;
|
||||
}
|
||||
|
||||
if (f->is_write && f->iovcnt > 0) {
|
||||
if (f->is_write) {
|
||||
if (f->ops->writev_buffer) {
|
||||
ret = f->ops->writev_buffer(f->opaque, f->iov, f->iovcnt);
|
||||
if (ret >= 0) {
|
||||
f->pos += ret;
|
||||
if (f->iovcnt > 0) {
|
||||
ret = f->ops->writev_buffer(f->opaque, f->iov, f->iovcnt);
|
||||
}
|
||||
} else {
|
||||
for (i = 0; i < f->iovcnt && ret >= 0; i++) {
|
||||
ret = f->ops->put_buffer(f->opaque, f->iov[i].iov_base, f->pos,
|
||||
f->iov[i].iov_len);
|
||||
if (ret >= 0) {
|
||||
f->pos += ret;
|
||||
}
|
||||
if (f->buf_index > 0) {
|
||||
ret = f->ops->put_buffer(f->opaque, f->buf, f->pos, f->buf_index);
|
||||
}
|
||||
}
|
||||
if (ret >= 0) {
|
||||
f->pos += ret;
|
||||
}
|
||||
f->buf_index = 0;
|
||||
f->iovcnt = 0;
|
||||
}
|
||||
@ -640,6 +637,11 @@ static void add_to_iovec(QEMUFile *f, const uint8_t *buf, int size)
|
||||
|
||||
void qemu_put_buffer_async(QEMUFile *f, const uint8_t *buf, int size)
|
||||
{
|
||||
if (!f->ops->writev_buffer) {
|
||||
qemu_put_buffer(f, buf, size);
|
||||
return;
|
||||
}
|
||||
|
||||
if (f->last_error) {
|
||||
return;
|
||||
}
|
||||
@ -673,8 +675,17 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size)
|
||||
if (l > size)
|
||||
l = size;
|
||||
memcpy(f->buf + f->buf_index, buf, l);
|
||||
f->buf_index += l;
|
||||
qemu_put_buffer_async(f, f->buf + (f->buf_index - l), l);
|
||||
f->bytes_xfer += size;
|
||||
if (f->ops->writev_buffer) {
|
||||
add_to_iovec(f, f->buf + f->buf_index, l);
|
||||
f->buf_index += l;
|
||||
} else {
|
||||
f->is_write = 1;
|
||||
f->buf_index += l;
|
||||
if (f->buf_index == IO_BUF_SIZE) {
|
||||
qemu_fflush(f);
|
||||
}
|
||||
}
|
||||
if (qemu_file_get_error(f)) {
|
||||
break;
|
||||
}
|
||||
@ -697,8 +708,16 @@ void qemu_put_byte(QEMUFile *f, int v)
|
||||
|
||||
f->buf[f->buf_index] = v;
|
||||
f->bytes_xfer++;
|
||||
add_to_iovec(f, f->buf + f->buf_index, 1);
|
||||
f->buf_index++;
|
||||
if (f->ops->writev_buffer) {
|
||||
add_to_iovec(f, f->buf + f->buf_index, 1);
|
||||
f->buf_index++;
|
||||
} else {
|
||||
f->is_write = 1;
|
||||
f->buf_index++;
|
||||
if (f->buf_index == IO_BUF_SIZE) {
|
||||
qemu_fflush(f);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
static void qemu_file_skip(QEMUFile *f, int size)
|
||||
|
Loading…
Reference in New Issue
Block a user