From: Jason Xing <kernelxing@xxxxxxxxxxx> When we encounter some performance issue and then get lost on how to tune the budget limit and time limit in net_rx_action() function, we can separately counting both of them to avoid the confusion. Signed-off-by: Jason Xing <kernelxing@xxxxxxxxxxx> --- v2: 1) change the coding style suggested by Stephen and Simon 2) Keep the display of the old data (time_squeeze) untouched suggested by Kui-Feng Link: https://lore.kernel.org/lkml/20230311163614.92296-1-kerneljasonxing@xxxxxxxxx/ --- include/linux/netdevice.h | 1 + net/core/dev.c | 12 ++++++++---- net/core/net-procfs.c | 9 ++++++--- 3 files changed, 15 insertions(+), 7 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 6a14b7b11766..5736311a2133 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -3157,6 +3157,7 @@ struct softnet_data { /* stats */ unsigned int processed; unsigned int time_squeeze; + unsigned int budget_squeeze; #ifdef CONFIG_RPS struct softnet_data *rps_ipi_list; #endif diff --git a/net/core/dev.c b/net/core/dev.c index 253584777101..1518a366783b 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6637,6 +6637,7 @@ static __latent_entropy void net_rx_action(struct softirq_action *h) unsigned long time_limit = jiffies + usecs_to_jiffies(READ_ONCE(netdev_budget_usecs)); int budget = READ_ONCE(netdev_budget); + bool done = false; LIST_HEAD(list); LIST_HEAD(repoll); @@ -6644,7 +6645,7 @@ static __latent_entropy void net_rx_action(struct softirq_action *h) list_splice_init(&sd->poll_list, &list); local_irq_enable(); - for (;;) { + while (!done) { struct napi_struct *n; skb_defer_free_flush(sd); @@ -6662,10 +6663,13 @@ static __latent_entropy void net_rx_action(struct softirq_action *h) * Allow this to run for 2 jiffies since which will allow * an average latency of 1.5/HZ. */ - if (unlikely(budget <= 0 || - time_after_eq(jiffies, time_limit))) { + if (unlikely(budget <= 0)) { + sd->budget_squeeze++; + done = true; + } + if (unlikely(time_after_eq(jiffies, time_limit))) { sd->time_squeeze++; - break; + done = true; } } diff --git a/net/core/net-procfs.c b/net/core/net-procfs.c index 2809b663e78d..25810ee46a04 100644 --- a/net/core/net-procfs.c +++ b/net/core/net-procfs.c @@ -179,14 +179,17 @@ static int softnet_seq_show(struct seq_file *seq, void *v) */ seq_printf(seq, "%08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x " - "%08x %08x\n", - sd->processed, sd->dropped, sd->time_squeeze, 0, + "%08x %08x %08x %08x\n", + sd->processed, sd->dropped, + sd->time_squeeze + sd->budget_squeeze, /* keep it untouched */ + 0, 0, 0, 0, 0, /* was fastroute */ 0, /* was cpu_collision */ sd->received_rps, flow_limit_count, softnet_backlog_len(sd), /* keep it untouched */ (int)seq->index, - softnet_input_pkt_queue_len(sd), softnet_process_queue_len(sd)); + softnet_input_pkt_queue_len(sd), softnet_process_queue_len(sd), + sd->time_squeeze, sd->budget_squeeze); return 0; } -- 2.37.3
