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SubjectRe: [ltt-dev] [PATCH] add tracepoints to track change in napi states on network receive
* Neil Horman (nhorman@tuxdriver.com) wrote:
> Hey there-
> I thought it would be handy to track the napi receive state of different
> network devices using ltt. This patch adds trace points to indicate when a napi
> instance has been scheduled, when its serviced and when it completes.
>

Sounds great, see comments below,

> Regards
> Neil
>
> Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
>
>
> include/linux/netdevice.h | 4 ++++
> include/trace/netdevice.h | 36 ++++++++++++++++++++++++++++++++++++
> ltt/probes/net-trace.c | 22 ++++++++++++++++++++++
> net/core/dev.c | 6 +++++-
> 4 files changed, 67 insertions(+), 1 deletion(-)
>
>
> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
> index 488c56e..9f35f84 100644
> --- a/include/linux/netdevice.h
> +++ b/include/linux/netdevice.h
> @@ -43,6 +43,8 @@
>
> #include <net/net_namespace.h>
>
> +#include <trace/netdevice.h>
> +
> struct vlan_group;
> struct ethtool_ops;
> struct netpoll_info;
> @@ -386,6 +388,7 @@ static inline void napi_complete(struct napi_struct *n)
> local_irq_save(flags);
> __napi_complete(n);
> local_irq_restore(flags);
> + trace_napi_complete(n);
> }
>
> /**
> @@ -1726,6 +1729,7 @@ static inline int skb_bond_should_drop(struct sk_buff *skb)
> return 0;
> }
>
> +
> #endif /* __KERNEL__ */
>
> #endif /* _LINUX_DEV_H */
> diff --git a/include/trace/netdevice.h b/include/trace/netdevice.h
> new file mode 100644
> index 0000000..c75030b
> --- /dev/null
> +++ b/include/trace/netdevice.h
> @@ -0,0 +1,36 @@
> +#ifndef _INCLUDE_NETDEVICE_H_
> +#define _INCLUDE_NETDEVICE_H_
> +
> +#include <linux/timer.h>
> +#include <linux/delay.h>
> +#include <asm/atomic.h>
> +#include <asm/cache.h>
> +#include <asm/byteorder.h>
> +
> +#include <linux/device.h>
> +#include <linux/percpu.h>
> +#include <linux/dmaengine.h>
> +#include <linux/workqueue.h>
> +
> +#include <net/net_namespace.h>
> +

Hrm ? Do we need all these includes ?

> +/* Tracepoints */
> +
> +/*
> + * Note this is actually the trace for __netif_rx_schedule
> + * since I wanted to trace every call which had us set the RX_SCHED bit

Could you put this comment in the 3rd person ? Also, I wonder if that
mean there might be other cause for schedule we would not trace ?


> + */
> +DEFINE_TRACE(napi_schedule,
> + TPPROTO(struct napi_struct *n),
> + TPARGS(n));
> +
> +DEFINE_TRACE(napi_poll,
> + TPPROTO(struct napi_struct *n),
> + TPARGS(n));
> +
> +DEFINE_TRACE(napi_complete,
> + TPPROTO(struct napi_struct *n),
> + TPARGS(n));
> +
> +#endif
> +
> diff --git a/ltt/probes/net-trace.c b/ltt/probes/net-trace.c
> index bac2b21..3de1ff8 100644
> --- a/ltt/probes/net-trace.c
> +++ b/ltt/probes/net-trace.c
> @@ -9,6 +9,7 @@
> #include <trace/ipv4.h>
> #include <trace/ipv6.h>
> #include <trace/socket.h>
> +#include <trace/netdevice.h>
>
> void probe_net_dev_xmit(struct sk_buff *skb)
> {
> @@ -104,6 +105,27 @@ void probe_socket_call(int call, unsigned long a0)
> "call %d a0 %lu", call, a0);
> }
>
> +void probe_napi_schedule(struct napi_struct *n)
> +{
> + trace_mark_tp(net_napi_schedule, napi_schedule, probe_napi_schedule,
> + "schedule napi instance %p, dev %s",


Field names should have no space, e.g. :

"napi_struct %p name %s"

Mathieu

> + n, n->dev->name);
> +}
> +
> +void probe_napi_poll(struct napi_struct *n)
> +{
> + trace_mark_tp(net_napi_poll, napi_poll, probe_napi_poll,
> + "service napi instance %p, dev %s",
> + n, n->dev->name);
> +}
> +
> +void probe_napi_complete(struct napi_struct *n)
> +{
> + trace_mark_tp(net_napi_complete, napi_complete, probe_napi_complete,
> + "complete napi instance %p, dev %s",
> + n, n->dev->name);
> +}
> +
> MODULE_LICENSE("GPL");
> MODULE_AUTHOR("Mathieu Desnoyers");
> MODULE_DESCRIPTION("Net Tracepoint Probes");
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 836fe6e..6021010 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -2329,6 +2329,8 @@ void __napi_schedule(struct napi_struct *n)
> {
> unsigned long flags;
>
> + trace_napi_poll(n);
> +
> local_irq_save(flags);
> list_add_tail(&n->poll_list, &__get_cpu_var(softnet_data).poll_list);
> __raise_softirq_irqoff(NET_RX_SOFTIRQ);
> @@ -2380,8 +2382,10 @@ static void net_rx_action(struct softirq_action *h)
> * accidently calling ->poll() when NAPI is not scheduled.
> */
> work = 0;
> - if (test_bit(NAPI_STATE_SCHED, &n->state))
> + if (test_bit(NAPI_STATE_SCHED, &n->state)) {
> + trace_napi_poll(n);
> work = n->poll(n, weight);
> + }
>
> WARN_ON_ONCE(work > weight);
>
> --
> /****************************************************
> * Neil Horman <nhorman@tuxdriver.com>
> * Software Engineer, Red Hat
> ****************************************************/
>
> _______________________________________________
> ltt-dev mailing list
> ltt-dev@lists.casi.polymtl.ca
> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
>

--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68


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