Add a tracepoint to help debug napi_complete_done. Users who set
defer_hard_irqs and the GRO timer can use this tracepoint to better
understand what impact these options have when their NIC driver calls
napi_complete_done.
perf trace can be used to enable the tracepoint and the output can be
examined to determine which settings should be adjusted.
$ sudo perf trace -e napi:napi_complete_done -a --call-graph=fp --libtraceevent_print
356.774 :0/0 napi:napi_complete_done(napi_complete_done on napi struct 0xffff88e052f02010 dev vlan100 irq_defers_remaining 2 timeout 20000 work_done 0 ret 0)
napi_complete_done ([kernel.kallsyms])
napi_complete_done ([kernel.kallsyms])
i40e_napi_poll ([i40e])
__napi_poll ([kernel.kallsyms])
net_rx_action ([kernel.kallsyms])
__do_softirq ([kernel.kallsyms])
sysvec_apic_timer_interrupt ([kernel.kallsyms])
asm_sysvec_apic_timer_interrupt ([kernel.kallsyms])
intel_idle_irq ([kernel.kallsyms])
cpuidle_enter_state ([kernel.kallsyms])
cpuidle_enter ([kernel.kallsyms])
do_idle ([kernel.kallsyms])
cpu_startup_entry ([kernel.kallsyms])
[0x243d98] ([kernel.kallsyms])
secondary_startup_64_no_verify ([kernel.kallsyms])
Signed-off-by: Joe Damato <[email protected]>
---
include/trace/events/napi.h | 29 +++++++++++++++++++++++++++++
net/core/dev.c | 2 ++
2 files changed, 31 insertions(+)
diff --git a/include/trace/events/napi.h b/include/trace/events/napi.h
index 6678cf8..e8473d3 100644
--- a/include/trace/events/napi.h
+++ b/include/trace/events/napi.h
@@ -11,6 +11,35 @@
#define NO_DEV "(no_device)"
+TRACE_EVENT(napi_complete_done,
+ TP_PROTO(struct napi_struct *napi, int hard_irq_defer, unsigned long timeout,
+ int work_done, bool ret),
+
+ TP_ARGS(napi, hard_irq_defer, timeout, work_done, ret),
+
+ TP_STRUCT__entry(
+ __field( struct napi_struct *, napi)
+ __string( dev_name, napi->dev ? napi->dev->name : NO_DEV)
+ __field( int, hard_irq_defer)
+ __field( unsigned long, timeout)
+ __field( int, work_done)
+ __field( int, ret)
+ ),
+
+ TP_fast_assign(
+ __entry->napi = napi;
+ __assign_str(dev_name, napi->dev ? napi->dev->name : NO_DEV);
+ __entry->hard_irq_defer = hard_irq_defer;
+ __entry->timeout = timeout;
+ __entry->work_done = work_done;
+ __entry->ret = ret;
+ ),
+
+ TP_printk("napi_complete_done on napi struct %p dev %s irq_defers_remaining %d timeout %lu work_done %d ret %d",
+ __entry->napi, __get_str(dev_name), __entry->hard_irq_defer,
+ __entry->timeout, __entry->work_done, __entry->ret)
+);
+
TRACE_EVENT(napi_poll,
TP_PROTO(struct napi_struct *napi, int work, int budget),
diff --git a/net/core/dev.c b/net/core/dev.c
index fa53830..e601f97 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6091,6 +6091,8 @@ bool napi_complete_done(struct napi_struct *n, int work_done)
if (timeout)
hrtimer_start(&n->timer, ns_to_ktime(timeout),
HRTIMER_MODE_REL_PINNED);
+
+ trace_napi_complete_done(n, n->defer_hard_irqs_count, timeout, work_done, ret);
return ret;
}
EXPORT_SYMBOL(napi_complete_done);
--
2.7.4