Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-10 22:21:40 +00:00
Code Issues Packages Projects Releases Wiki Activity

rxrpc: Reduce unnecessary ack transmission

Browse Source 
rxrpc_recvmsg_data() schedules an ACK to be transmitted every time at least
two packets have been consumed and any time it runs out of data and would
return -EAGAIN to the caller.  Both events may occur within a single loop,
however, and if the I/O thread is quick enough it may send duplicate ACKs.

The ACKs are sent to inform the peer that more space has been made in the
local Rx window, but the I/O thread is going to send an ACK every couple of
DATA packets anyway, so we end up sending a lot more ACKs than we really
need to.

So reduce the rate at which recvmsg() schedules ACKs, such that if the I/O
thread sends ACKs at its normal faster rate, recvmsg() won't actually
schedule ACKs until the Rx flow stops (call->rx_consumed is cleared any
time we transmit an ACK for that call, resetting the counter used by
recvmsg).

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
This commit is contained in:
David Howells 2023-01-31 21:40:18 +00:00
parent f789bff2de
commit 5a2c5a5b08
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
net/rxrpc/recvmsg.c
View File

@ -137,7 +137,7 @@ static void rxrpc_rotate_rx_window(struct rxrpc_call *call)
/* Check to see if there's an ACK that needs sending. */
acked = atomic_add_return(call->rx_consumed - old_consumed,
&call->ackr_nr_consumed);
if (acked > 2 &&
if (acked > 8 &&
!test_and_set_bit(RXRPC_CALL_RX_IS_IDLE, &call->flags))
rxrpc_poke_call(call, rxrpc_call_poke_idle);
}