[Tarantool-patches] [PATCH] relay: yield explicitly every N sent rows

[Cyrill Gorcunov]

On Fri, Feb 12, 2021 at 02:25:41PM +0300, Serge Petrenko wrote:
> @@ -836,11 +836,20 @@ relay_send(struct relay *relay, struct xrow_header *packet)
>  {
>  	ERROR_INJECT_YIELD(ERRINJ_RELAY_SEND_DELAY);
>  
> +	static uint64_t row_cnt = 0;
>  	packet->sync = relay->sync;
>  	relay->last_row_time = ev_monotonic_now(loop());
>  	coio_write_xrow(&relay->io, packet);
>  	fiber_gc();
>  
> +	/*
> +	 * It may happen that the socket is always ready for write, so yield
> +	 * explicitly every now and then to not block the event loop.
> +	 */
> +	row_cnt++;
> +	if (row_cnt % WAL_ROWS_PER_YIELD == 0) {
> +		fiber_sleep(0);
> +	}

Serge, if I'm not missing something obvious, this row counter is
related to xstream->rows? So maybe define this type as size_t instead,
to be consistent with another occurence of WAL_ROWS_PER_YIELD. Say,

	static size_t row_cnt = 0;
	...
	if (++row_cnt % WAL_ROWS_PER_YIELD == 0)
		fiber_sleep(0);

I'm fine with uint64_t as well, just out of curiosity.