On 05/22/2012 09:32 PM, Juan Quintela wrote:
> cheking each 64 pages is a random magic number as good as any other.
s/cheking/checking
> We don't want to test too many times, but on the other hand,
> qemu_get_clock_ns() is not so expensive either. We want to be sure
> that we spent less than 50ms (half of buffered_file timer), if we
> spent more than 100ms, all the accounting got wrong.
>
> Signed-off-by: Juan Quintela <quint...@redhat.com>
> ---
> arch_init.c | 15 +++++++++++++++
> 1 files changed, 15 insertions(+), 0 deletions(-)
>
> diff --git a/arch_init.c b/arch_init.c
> index 76a3d4e..2aa77ff 100644
> --- a/arch_init.c
> +++ b/arch_init.c
> @@ -296,6 +296,7 @@ int ram_save_live(QEMUFile *f, int stage, void *opaque)
> uint64_t bytes_transferred_last;
> double bwidth = 0;
> int ret;
> + int i;
>
> if (stage < 0) {
> memory_global_dirty_log_stop();
> @@ -335,6 +336,7 @@ int ram_save_live(QEMUFile *f, int stage, void *opaque)
> bytes_transferred_last = bytes_transferred;
> bwidth = qemu_get_clock_ns(rt_clock);
>
> + i = 0;
> while ((ret = qemu_file_rate_limit(f)) == 0) {
> int bytes_sent;
>
> @@ -343,6 +345,19 @@ int ram_save_live(QEMUFile *f, int stage, void *opaque)
> if (bytes_sent == 0) { /* no more blocks */
> break;
> }
> + /* we want to check in the 1st loop, just in case it was the 1st time
> + and we had to sync the dirty bitmap.
> + qemu_get_clock_ns() is a bit expensive, so we only check each some
> + iterations
> + */
> + if ((i & 63) == 0) {
> + uint64_t t1 = (qemu_get_clock_ns(rt_clock) - bwidth) / 1000000;
> + if (t1 > 50) { /* 50ms, half buffered_file limit */
can't we use a constant ?
> + printf("big delay %ld milliseconds, %d iterations\n", t1, i);
printf ?
Orit
> + break;
> + }
> + }
> + i++;
> }
>
> if (ret < 0) {
