On Thu, Jul 19, 2018 at 08:15:15PM +0800, guangrong.xiao@xxxxxxxxx wrote:
> @@ -1597,6 +1608,24 @@ static void migration_update_rates(RAMState *rs, int64_t end_time)
> rs->xbzrle_cache_miss_prev) / iter_count;
> rs->xbzrle_cache_miss_prev = xbzrle_counters.cache_miss;
> }
> +
> + if (migrate_use_compression()) {
> + uint64_t comp_pages;
> +
> + compression_counters.busy_rate = (double)(compression_counters.busy -
> + rs->compress_thread_busy_prev) / iter_count;
Here I'm not sure it's correct...
"iter_count" stands for ramstate.iterations. It's increased per
ram_find_and_save_block(), so IMHO it might contain multiple guest
pages. However compression_counters.busy should be per guest page.
> + rs->compress_thread_busy_prev = compression_counters.busy;
> +
> + comp_pages = compression_counters.pages - rs->compress_pages_prev;
> + if (comp_pages) {
> + compression_counters.compression_rate =
> + (double)(compression_counters.reduced_size -
> + rs->compress_reduced_size_prev) /
> + (comp_pages * TARGET_PAGE_SIZE);
> + rs->compress_pages_prev = compression_counters.pages;
> + rs->compress_reduced_size_prev = compression_counters.reduced_size;
> + }
> + }
> }
>
> static void migration_bitmap_sync(RAMState *rs)
> @@ -1872,6 +1901,9 @@ static void flush_compressed_data(RAMState *rs)
> qemu_mutex_lock(&comp_param[idx].mutex);
> if (!comp_param[idx].quit) {
> len = qemu_put_qemu_file(rs->f, comp_param[idx].file);
> + /* 8 means a header with RAM_SAVE_FLAG_CONTINUE. */
> + compression_counters.reduced_size += TARGET_PAGE_SIZE - len + 8;
I would agree with Dave here - why we store the "reduced size" instead
of the size of the compressed data (which I think should be len - 8)?
Meanwhile, would a helper be nicer? Like:
void migrate_compressed_page_stats_update(int xfer_size)
{
/* Removing the offset header in save_page_header() */
compression_counters.compressed_size = xfer_size - 8;
compression_counters.pages++;
ram_counters.transferred += bytes_xmit;
}
> + compression_counters.pages++;
> ram_counters.transferred += len;
> }
> qemu_mutex_unlock(&comp_param[idx].mutex);
> @@ -1903,6 +1935,10 @@ retry:
> qemu_cond_signal(&comp_param[idx].cond);
> qemu_mutex_unlock(&comp_param[idx].mutex);
> pages = 1;
> + /* 8 means a header with RAM_SAVE_FLAG_CONTINUE. */
> + compression_counters.reduced_size += TARGET_PAGE_SIZE -
> + bytes_xmit + 8;
> + compression_counters.pages++;
> ram_counters.transferred += bytes_xmit;
> break;
> }
Regards,
--
Peter Xu
