Re: [PATCH] NET : convert network timestamps to ktime_t
From: Eric Dumazet <hidden>
Date: 2007-03-02 22:46:30
Stephen Hemminger a écrit :
On Fri, 2 Mar 2007 15:38:41 +0100 Eric Dumazet [off-list ref] wrote:quoted
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, ...)You missed a couple of spots.
Arg yes...
quoted hunk ↗ jump to hunk
--- tcp-2.6.orig/net/sunrpc/svcsock.c 2007-03-02 12:50:45.000000000 -0800 +++ tcp-2.6/net/sunrpc/svcsock.c 2007-03-02 12:58:28.000000000 -0800@@ -805,16 +805,9 @@ /* possibly an icmp error */ dprintk("svc: recvfrom returned error %d\n", -err); } - if (skb->tstamp.off_sec == 0) { - struct timeval tv; - tv.tv_sec = xtime.tv_sec; - tv.tv_usec = xtime.tv_nsec / NSEC_PER_USEC; - skb_set_timestamp(skb, &tv); - /* Don't enable netstamp, sunrpc doesn't - need that much accuracy */ - } - skb_get_timestamp(skb, &svsk->sk_sk->sk_stamp); + svsk->sk_sk->sk_stamp = (skb->tstamp.tv64 != 0) ? skb->tstamp + : ktime_get_real();
Well, if we want to stay in the spirit of old code, we probably want to use current_kernel_time() (+ timespec_to_ktime()), because its less expensive. And also setting the skb tstamp, no ?