netdev - Re: [PATCH v2 net-next] tcp: switch rtt estimations to usec resolution

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 27 Feb 2014 22:14:32 -0800
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Andi Kleen <andi@...stfloor.org>
Cc:	Julian Anastasov <ja@....bg>, David Miller <davem@...emloft.net>,
	netdev <netdev@...r.kernel.org>,
	Yuchung Cheng <ycheng@...gle.com>,
	Neal Cardwell <ncardwell@...gle.com>,
	Larry Brakmo <brakmo@...gle.com>
Subject: Re: [PATCH v2 net-next] tcp: switch rtt estimations to usec
 resolution

On Thu, 2014-02-27 at 21:20 -0800, Andi Kleen wrote:
> Eric Dumazet <eric.dumazet@...il.com> writes:
> >  
> > -	rtt_update = tcp_ack_update_rtt(sk, flag, seq_rtt, sack_rtt);
> > +	if (first_ackt.tv64) {
> > +		ktime_t curt = ktime_get_real();
> 
> Sorry I'm late to the party. One problem is that if a system doesn't use
> TSC for some reason this will be incredibly slow (unfortunately this
> happens for various reasons). Perhaps we need a
> ktime_get_real_but_use_jiffies_if_slow() or somesuch.

Right, so I cooked this instead :

http://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git/commit/?id=363ec392352e55c61ce2799c3f15f89f9429bba7

Is this OK or do you see a problem with this ?

Thanks !


--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html