On 3/11/23 08:36, Jason Xing wrote:
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>
---
note: this commit is based on the link as below:
https://lore.kernel.org/lkml/20230311151756.83302-1-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..bed7a68fdb5d 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 is_continue = true;
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 (;;) {
+ for (; is_continue;) {
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++;
+ is_continue = false;
+ }
+ if (unlikely(time_after_eq(jiffies, time_limit))) {
sd->time_squeeze++;
- break;
+ is_continue = false;
}
}
diff --git a/net/core/net-procfs.c b/net/core/net-procfs.c
index 97a304e1957a..4d1a499d7c43 100644
--- a/net/core/net-procfs.c
+++ b/net/core/net-procfs.c
@@ -174,14 +174,17 @@ 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,
+ 0, /* was old way to count time squeeze */
Should we show a proximate number? For example,
sd->time_squeeze + sd->bud_squeeze.
+ 0,
0, 0, 0, 0, /* was fastroute */
0, /* was cpu_collision */
sd->received_rps, flow_limit_count,
0, /* was len of two backlog queues */
(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;
}
