From 24f8b2385e03a4f4c8dac513d03b5eaa475822b9 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Mon, 3 Nov 2008 17:14:38 -0800 Subject: [PATCH] net: increase receive packet quantum This patch gets about 1.25% back on tbench regression. My change to NAPI for multiqueue support changed the time limit on network receive processing. Under sustained loads like tbench, this can cause the receiver to reschedule prematurely. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- net/core/dev.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 3a2b8be9e67b..8f9d3b38a44b 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2373,7 +2373,7 @@ EXPORT_SYMBOL(__napi_schedule); static void net_rx_action(struct softirq_action *h) { struct list_head *list = &__get_cpu_var(softnet_data).poll_list; - unsigned long start_time = jiffies; + unsigned long time_limit = jiffies + 2; int budget = netdev_budget; void *have; @@ -2384,13 +2384,10 @@ static void net_rx_action(struct softirq_action *h) int work, weight; /* If softirq window is exhuasted then punt. - * - * Note that this is a slight policy change from the - * previous NAPI code, which would allow up to 2 - * jiffies to pass before breaking out. The test - * used to be "jiffies - start_time > 1". + * Allow this to run for 2 jiffies since which will allow + * an average latency of 1.5/HZ. */ - if (unlikely(budget <= 0 || jiffies != start_time)) + if (unlikely(budget <= 0 || time_after(jiffies, time_limit))) goto softnet_break; local_irq_enable(); -- 2.30.2