Subject: Re: [PATCH] NET : convert network timestamps to ktime_t

From: Stephen Hemminger <[email-masked]>
Date: Fri, 2 Mar 2007 08:27:23 -0800

On Fri, 2 Mar 2007 15:38:41 +0100
Eric Dumazet <[email-masked]> wrote:

> 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, ...)

This is even better. Also comparing ktime_t's is easier if some code needs
to do that.