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

[Serge Petrenko]

12.02.2021 14:37, Cyrill Gorcunov пишет:
> 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,

Thanks for the review!
Yes, it serves the same purpose.
No problem, let it be size_t, updated.

> 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.

Looks fine. My bad, I didn't pay enough attention when writing the patch.
=========================================================================
diff --git a/src/box/relay.cc b/src/box/relay.cc
index afc57dfbc..1d8edf116 100644
--- a/src/box/relay.cc
+++ b/src/box/relay.cc
@@ -836,7 +836,7 @@ relay_send(struct relay *relay, struct xrow_header 
*packet)
  {
      ERROR_INJECT_YIELD(ERRINJ_RELAY_SEND_DELAY);

-    static uint64_t row_cnt = 0;
+    static size_t row_cnt = 0;
      packet->sync = relay->sync;
      relay->last_row_time = ev_monotonic_now(loop());
      coio_write_xrow(&relay->io, packet);
@@ -846,10 +846,9 @@ relay_send(struct relay *relay, struct xrow_header 
*packet)
       * 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) {
+    if (++row_cnt % WAL_ROWS_PER_YIELD == 0)
          fiber_sleep(0);
-    }
+
      struct errinj *inj = errinj(ERRINJ_RELAY_TIMEOUT, ERRINJ_DOUBLE);
      if (inj != NULL && inj->dparam > 0)
          fiber_sleep(inj->dparam);

-- 
Serge Petrenko