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]

Message-ID: <87fvn3dd9i.fsf@tassilo.jf.intel.com>
Date:	Thu, 27 Feb 2014 21:20:25 -0800
From:	Andi Kleen <andi@...stfloor.org>
To:	Eric Dumazet <eric.dumazet@...il.com>
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

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.

-andi

-- 
ak@...ux.intel.com -- Speaking for myself only
--
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