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authorWillem de Bruijn <willemb@google.com>2014-08-05 02:11:48 (GMT)
committerDavid S. Miller <davem@davemloft.net>2014-08-05 23:35:54 (GMT)
commite7fd2885385157d46c85f282fc6d7d297db43e1f (patch)
tree14e9d00ed87b2b45882c8cb8dd1b9b4d221724f8
parent09c2d251b70723650ba47e83571ff49281320f7c (diff)
downloadlinux-e7fd2885385157d46c85f282fc6d7d297db43e1f.tar.xz
net-timestamp: SCHED timestamp on entering packet scheduler
Kernel transmit latency is often incurred in the packet scheduler. Introduce a new timestamp on transmission just before entering the scheduler. When data travels through multiple devices (bonding, tunneling, ...) each device will export an individual timestamp. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/skbuff.h11
-rw-r--r--include/uapi/linux/errqueue.h1
-rw-r--r--include/uapi/linux/net_tstamp.h3
-rw-r--r--net/core/dev.c4
-rw-r--r--net/core/skbuff.c16
-rw-r--r--net/socket.c3
6 files changed, 31 insertions, 7 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 0e35b3a..50e1e9b 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -229,7 +229,7 @@ enum {
/* generate hardware time stamp */
SKBTX_HW_TSTAMP = 1 << 0,
- /* generate software time stamp */
+ /* generate software time stamp when queueing packet to NIC */
SKBTX_SW_TSTAMP = 1 << 1,
/* device driver is going to provide hardware time stamp */
@@ -247,9 +247,12 @@ enum {
* all frags to avoid possible bad checksum
*/
SKBTX_SHARED_FRAG = 1 << 5,
+
+ /* generate software time stamp when entering packet scheduling */
+ SKBTX_SCHED_TSTAMP = 1 << 6,
};
-#define SKBTX_ANY_SW_TSTAMP SKBTX_SW_TSTAMP
+#define SKBTX_ANY_SW_TSTAMP (SKBTX_SW_TSTAMP | SKBTX_SCHED_TSTAMP)
#define SKBTX_ANY_TSTAMP (SKBTX_HW_TSTAMP | SKBTX_ANY_SW_TSTAMP)
/*
@@ -2695,6 +2698,10 @@ static inline bool skb_defer_rx_timestamp(struct sk_buff *skb)
void skb_complete_tx_timestamp(struct sk_buff *skb,
struct skb_shared_hwtstamps *hwtstamps);
+void __skb_tstamp_tx(struct sk_buff *orig_skb,
+ struct skb_shared_hwtstamps *hwtstamps,
+ struct sock *sk, int tstype);
+
/**
* skb_tstamp_tx - queue clone of skb with send time stamps
* @orig_skb: the original outgoing packet
diff --git a/include/uapi/linux/errqueue.h b/include/uapi/linux/errqueue.h
index accee72..17437cf 100644
--- a/include/uapi/linux/errqueue.h
+++ b/include/uapi/linux/errqueue.h
@@ -39,6 +39,7 @@ struct scm_timestamping {
*/
enum {
SCM_TSTAMP_SND, /* driver passed skb to NIC, or HW */
+ SCM_TSTAMP_SCHED, /* data entered the packet scheduler */
};
#endif /* _UAPI_LINUX_ERRQUEUE_H */
diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h
index 1e861d2..6073384 100644
--- a/include/uapi/linux/net_tstamp.h
+++ b/include/uapi/linux/net_tstamp.h
@@ -21,8 +21,9 @@ enum {
SOF_TIMESTAMPING_SYS_HARDWARE = (1<<5),
SOF_TIMESTAMPING_RAW_HARDWARE = (1<<6),
SOF_TIMESTAMPING_OPT_ID = (1<<7),
+ SOF_TIMESTAMPING_TX_SCHED = (1<<8),
- SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_ID,
+ SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_TX_SCHED,
SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) |
SOF_TIMESTAMPING_LAST
};
diff --git a/net/core/dev.c b/net/core/dev.c
index b370230..1c15b18 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -132,6 +132,7 @@
#include <linux/hashtable.h>
#include <linux/vmalloc.h>
#include <linux/if_macvlan.h>
+#include <linux/errqueue.h>
#include "net-sysfs.h"
@@ -2876,6 +2877,9 @@ static int __dev_queue_xmit(struct sk_buff *skb, void *accel_priv)
skb_reset_mac_header(skb);
+ if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_SCHED_TSTAMP))
+ __skb_tstamp_tx(skb, NULL, skb->sk, SCM_TSTAMP_SCHED);
+
/* Disable soft irqs for various locks below. Also
* stops preemption for RCU.
*/
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 0df4f1d..9705c07 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3490,10 +3490,10 @@ int sock_queue_err_skb(struct sock *sk, struct sk_buff *skb)
}
EXPORT_SYMBOL(sock_queue_err_skb);
-void skb_tstamp_tx(struct sk_buff *orig_skb,
- struct skb_shared_hwtstamps *hwtstamps)
+void __skb_tstamp_tx(struct sk_buff *orig_skb,
+ struct skb_shared_hwtstamps *hwtstamps,
+ struct sock *sk, int tstype)
{
- struct sock *sk = orig_skb->sk;
struct sock_exterr_skb *serr;
struct sk_buff *skb;
int err;
@@ -3521,7 +3521,7 @@ void skb_tstamp_tx(struct sk_buff *orig_skb,
memset(serr, 0, sizeof(*serr));
serr->ee.ee_errno = ENOMSG;
serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
- serr->ee.ee_info = SCM_TSTAMP_SND;
+ serr->ee.ee_info = tstype;
if (sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
serr->ee.ee_data = skb_shinfo(skb)->tskey;
@@ -3530,6 +3530,14 @@ void skb_tstamp_tx(struct sk_buff *orig_skb,
if (err)
kfree_skb(skb);
}
+EXPORT_SYMBOL_GPL(__skb_tstamp_tx);
+
+void skb_tstamp_tx(struct sk_buff *orig_skb,
+ struct skb_shared_hwtstamps *hwtstamps)
+{
+ return __skb_tstamp_tx(orig_skb, hwtstamps, orig_skb->sk,
+ SCM_TSTAMP_SND);
+}
EXPORT_SYMBOL_GPL(skb_tstamp_tx);
void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)
diff --git a/net/socket.c b/net/socket.c
index 255d9b8..3a2778d 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -617,6 +617,9 @@ void sock_tx_timestamp(struct sock *sk, __u8 *tx_flags)
*tx_flags |= SKBTX_HW_TSTAMP;
if (sk->sk_tsflags & SOF_TIMESTAMPING_TX_SOFTWARE)
*tx_flags |= SKBTX_SW_TSTAMP;
+ if (sk->sk_tsflags & SOF_TIMESTAMPING_TX_SCHED)
+ *tx_flags |= SKBTX_SCHED_TSTAMP;
+
if (sock_flag(sk, SOCK_WIFI_STATUS))
*tx_flags |= SKBTX_WIFI_STATUS;
}