From b7aa0bf70c4afb9e38be25f5c0922498d0f8684c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 19 Apr 2007 16:16:32 -0700 Subject: [NET]: convert network timestamps to ktime_t We currently use a special structure (struct skb_timeval) and plain 'struct timeval' to store packet timestamps in sk_buffs and struct sock. This has some drawbacks : - Fixed resolution of micro second. - Waste of space on 64bit platforms where sizeof(struct timeval)=16 I suggest using ktime_t that is a nice abstraction of high resolution time services, currently capable of nanosecond resolution. As sizeof(ktime_t) is 8 bytes, using ktime_t in 'struct sock' permits a 8 byte shrink of this structure on 64bit architectures. Some other structures also benefit from this size reduction (struct ipq in ipv4/ip_fragment.c, struct frag_queue in ipv6/reassembly.c, ...) Once this ktime infrastructure adopted, we can more easily provide nanosecond resolution on top of it. (ioctl SIOCGSTAMPNS and/or SO_TIMESTAMPNS/SCM_TIMESTAMPNS) Note : this patch includes a bug correction in compat_sock_get_timestamp() where a "err = 0;" was missing (so this syscall returned -ENOENT instead of 0) Signed-off-by: Eric Dumazet CC: Stephen Hemminger CC: John find Signed-off-by: David S. Miller --- include/linux/skbuff.h | 26 +++++--------------------- 1 file changed, 5 insertions(+), 21 deletions(-) (limited to 'include/linux/skbuff.h') diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 5992f65b4184..f9441b5f8d13 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -27,6 +27,7 @@ #include #include #include +#include #define HAVE_ALLOC_SKB /* For the drivers to know */ #define HAVE_ALIGNABLE_SKB /* Ditto 8) */ @@ -156,11 +157,6 @@ struct skb_shared_info { #define SKB_DATAREF_SHIFT 16 #define SKB_DATAREF_MASK ((1 << SKB_DATAREF_SHIFT) - 1) -struct skb_timeval { - u32 off_sec; - u32 off_usec; -}; - enum { SKB_FCLONE_UNAVAILABLE, @@ -233,7 +229,7 @@ struct sk_buff { struct sk_buff *prev; struct sock *sk; - struct skb_timeval tstamp; + ktime_t tstamp; struct net_device *dev; int iif; /* 4 byte hole on 64 bit*/ @@ -1365,26 +1361,14 @@ extern void skb_add_mtu(int mtu); */ static inline void skb_get_timestamp(const struct sk_buff *skb, struct timeval *stamp) { - stamp->tv_sec = skb->tstamp.off_sec; - stamp->tv_usec = skb->tstamp.off_usec; + *stamp = ktime_to_timeval(skb->tstamp); } -/** - * skb_set_timestamp - set timestamp of a skb - * @skb: skb to set stamp of - * @stamp: pointer to struct timeval to get stamp from - * - * Timestamps are stored in the skb as offsets to a base timestamp. - * This function converts a struct timeval to an offset and stores - * it in the skb. - */ -static inline void skb_set_timestamp(struct sk_buff *skb, const struct timeval *stamp) +static inline void __net_timestamp(struct sk_buff *skb) { - skb->tstamp.off_sec = stamp->tv_sec; - skb->tstamp.off_usec = stamp->tv_usec; + skb->tstamp = ktime_get_real(); } -extern void __net_timestamp(struct sk_buff *skb); extern __sum16 __skb_checksum_complete(struct sk_buff *skb); -- cgit v1.2.3-59-g8ed1b