From 59361316afcb08569af21e1af83e89c7051c055a Mon Sep 17 00:00:00 2001 From: Jeff Kirsher Date: Thu, 2 Aug 2018 10:13:10 -0700 Subject: igb: reduce CPU0 latency when updating statistics This change is based off of the work and suggestion of Jan Jablonsky . The Watchdog workqueue in igb driver is scheduled every 2s for each network interface. That includes updating a statistics protected by spinlock. Function igb_update_stats in this case will be protected against preemption. According to number of a statistics registers (cca 60), processing this function might cause additional cpu load on CPU0. In case of statistics spinlock may be replaced with mutex, which reduce latency on CPU0. CC: Bernhard Kaindl CC: Jan Jablonsky Signed-off-by: Jeff Kirsher Tested-by: Aaron Brown Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/igb/igb_ethtool.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/net/ethernet/intel/igb/igb_ethtool.c') diff --git a/drivers/net/ethernet/intel/igb/igb_ethtool.c b/drivers/net/ethernet/intel/igb/igb_ethtool.c index c57671068245..7426060b678f 100644 --- a/drivers/net/ethernet/intel/igb/igb_ethtool.c +++ b/drivers/net/ethernet/intel/igb/igb_ethtool.c @@ -2295,7 +2295,7 @@ static void igb_get_ethtool_stats(struct net_device *netdev, int i, j; char *p; - spin_lock(&adapter->stats64_lock); + mutex_lock(&adapter->stats64_lock); igb_update_stats(adapter); for (i = 0; i < IGB_GLOBAL_STATS_LEN; i++) { @@ -2338,7 +2338,7 @@ static void igb_get_ethtool_stats(struct net_device *netdev, } while (u64_stats_fetch_retry_irq(&ring->rx_syncp, start)); i += IGB_RX_QUEUE_STATS_LEN; } - spin_unlock(&adapter->stats64_lock); + mutex_unlock(&adapter->stats64_lock); } static void igb_get_strings(struct net_device *netdev, u32 stringset, u8 *data) -- cgit v1.2.3