From 68c3e4fc8628b1487c965aabb29207249657eb5f Mon Sep 17 00:00:00 2001 From: Joshua Washington Date: Tue, 21 Mar 2023 10:23:32 -0700 Subject: gve: Cache link_speed value from device The link speed is never changed for the uptime of a VM, and the current implementation sends an admin queue command for each call. Admin queue command invocations have nontrivial overhead (e.g., VM exits), which can be disruptive to users if triggered frequently. Our telemetry data shows that there are VMs that make frequent calls to this admin queue command. Caching the result of the original admin queue command would eliminate the need to send multiple admin queue commands on subsequent calls to retrieve link speed. Fixes: 7e074d5a76ca ("gve: Enable Link Speed Reporting in the driver.") Signed-off-by: Joshua Washington Reviewed-by: Simon Horman Link: https://lore.kernel.org/r/20230321172332.91678-1-joshwash@google.com Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/google/gve/gve_ethtool.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'drivers/net/ethernet/google/gve') diff --git a/drivers/net/ethernet/google/gve/gve_ethtool.c b/drivers/net/ethernet/google/gve/gve_ethtool.c index ce574d097e28..5f81470843b4 100644 --- a/drivers/net/ethernet/google/gve/gve_ethtool.c +++ b/drivers/net/ethernet/google/gve/gve_ethtool.c @@ -537,7 +537,10 @@ static int gve_get_link_ksettings(struct net_device *netdev, struct ethtool_link_ksettings *cmd) { struct gve_priv *priv = netdev_priv(netdev); - int err = gve_adminq_report_link_speed(priv); + int err = 0; + + if (priv->link_speed == 0) + err = gve_adminq_report_link_speed(priv); cmd->base.speed = priv->link_speed; return err; -- cgit