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authorUrsula Braun <ursula.braun@linux.ibm.com>2018-07-18 15:22:49 +0200
committerDavid S. Miller <davem@davemloft.net>2018-07-18 10:58:27 -0700
commit99be51f11d51400f744632f3938445a8d4de8943 (patch)
tree0424d44df4eb59b5c47ed9dbfda4a0623ec2a91a
parentnet/nfc: Avoid stalls when nfc_alloc_send_skb() returned NULL. (diff)
downloadlinux-dev-99be51f11d51400f744632f3938445a8d4de8943.tar.xz
linux-dev-99be51f11d51400f744632f3938445a8d4de8943.zip
net/smc: optimize consumer cursor updates
The SMC protocol requires to send a separate consumer cursor update, if it cannot be piggybacked to updates of the producer cursor. Currently the decision to send a separate consumer cursor update just considers the amount of data already received by the socket program. It does not consider the amount of data already arrived, but not yet consumed by the receiver. Basing the decision on the difference between already confirmed and already arrived data (instead of difference between already confirmed and already consumed data), may lead to a somewhat earlier consumer cursor update send in fast unidirectional traffic scenarios, and thus to better throughput. Signed-off-by: Ursula Braun <ubraun@linux.ibm.com> Suggested-by: Thomas Richter <tmricht@linux.ibm.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/smc/smc_tx.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c
index cee666400752..f82886b7d1d8 100644
--- a/net/smc/smc_tx.c
+++ b/net/smc/smc_tx.c
@@ -495,7 +495,8 @@ out:
void smc_tx_consumer_update(struct smc_connection *conn, bool force)
{
- union smc_host_cursor cfed, cons;
+ union smc_host_cursor cfed, cons, prod;
+ int sender_free = conn->rmb_desc->len;
int to_confirm;
smc_curs_write(&cons,
@@ -505,11 +506,18 @@ void smc_tx_consumer_update(struct smc_connection *conn, bool force)
smc_curs_read(&conn->rx_curs_confirmed, conn),
conn);
to_confirm = smc_curs_diff(conn->rmb_desc->len, &cfed, &cons);
+ if (to_confirm > conn->rmbe_update_limit) {
+ smc_curs_write(&prod,
+ smc_curs_read(&conn->local_rx_ctrl.prod, conn),
+ conn);
+ sender_free = conn->rmb_desc->len -
+ smc_curs_diff(conn->rmb_desc->len, &prod, &cfed);
+ }
if (conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
force ||
((to_confirm > conn->rmbe_update_limit) &&
- ((to_confirm > (conn->rmb_desc->len / 2)) ||
+ ((sender_free <= (conn->rmb_desc->len / 2)) ||
conn->local_rx_ctrl.prod_flags.write_blocked))) {
if ((smc_cdc_get_slot_and_msg_send(conn) < 0) &&
conn->alert_token_local) { /* connection healthy */