On 03/21/2013 11:56 AM, Paolo Bonzini wrote:
> Il 21/03/2013 10:09, Orit Wasserman ha scritto:
>> All data is still copied into the static buffer.
>>
>> Signed-off-by: Orit Wasserman <owass...@redhat.com>
>> ---
>> savevm.c | 13 +++++++++++--
>> 1 file changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/savevm.c b/savevm.c
>> index ec64533..d5834ca 100644
>> --- a/savevm.c
>> +++ b/savevm.c
>> @@ -114,6 +114,7 @@ void qemu_announce_self(void)
>> /* savevm/loadvm support */
>>
>> #define IO_BUF_SIZE 32768
>> +#define MAX_IOV_SIZE 64
>
> You could use IOV_MAX, or min(IOV_MAX, 64).
Sure
The 64 should be tuned on a
> good 10G network...
You need to remember that iovec of 64 is equivalent to 32 guest pages which are
128K data. This is a large TCP packet that will be fragmented even with jumbo
frames.
I can make it configurable but not sure if it will be useful.
Micheal, what do you think?
Orit
>
> Paolo
>
>> struct QEMUFile {
>> const QEMUFileOps *ops;
>> @@ -129,6 +130,9 @@ struct QEMUFile {
>> int buf_size; /* 0 when writing */
>> uint8_t buf[IO_BUF_SIZE];
>>
>> + struct iovec iov[MAX_IOV_SIZE];
>> + unsigned int iovcnt;
>> +
>> int last_error;
>> };
>>
>> @@ -546,6 +550,7 @@ static void qemu_fflush(QEMUFile *f)
>> f->pos += f->buf_index;
>> }
>> f->buf_index = 0;
>> + f->iovcnt = 0;
>> }
>> if (ret < 0) {
>> qemu_file_set_error(f, ret);
>> @@ -638,12 +643,14 @@ 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->iov[f->iovcnt].iov_base = f->buf + f->buf_index;
>> + f->iov[f->iovcnt++].iov_len = l;
>> f->is_write = 1;
>> f->buf_index += l;
>> f->bytes_xfer += l;
>> buf += l;
>> size -= l;
>> - if (f->buf_index >= IO_BUF_SIZE) {
>> + if (f->buf_index >= IO_BUF_SIZE || f->iovcnt >= MAX_IOV_SIZE) {
>> qemu_fflush(f);
>> if (qemu_file_get_error(f)) {
>> break;
>> @@ -667,8 +674,10 @@ void qemu_put_byte(QEMUFile *f, int v)
>> f->buf[f->buf_index++] = v;
>> f->is_write = 1;
>> f->bytes_xfer += 1;
>> + f->iov[f->iovcnt].iov_base = f->buf + (f->buf_index - 1);
>> + f->iov[f->iovcnt++].iov_len = 1;
>>
>> - if (f->buf_index >= IO_BUF_SIZE) {
>> + if (f->buf_index >= IO_BUF_SIZE || f->iovcnt >= MAX_IOV_SIZE) {
>> qemu_fflush(f);
>> }
>> }
>>
>
