netdev - Re: Purpose of bit shifts in tcp_get

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] [day] [month] [year] [list]

Message-Id: <E1HpHOx-0001JW-00@gondolin.me.apana.org.au>
Date:	Sat, 19 May 2007 15:22:47 +1000
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	daniel.schaffrath@....com (Daniel Schaffrath)
Cc:	netdev@...r.kernel.org
Subject: Re: Purpose of bit shifts in tcp_get_info

Daniel Schaffrath <daniel.schaffrath@....com> wrote:
> 
> I was wondering what the purpose of the bit shifts in tcp_get_info  
> right after the jiffies conversion might be. What's the time unit  
> after that shift?
> 
>         info->tcpi_rtt = jiffies_to_usecs(tp->srtt)>>3;
>         info->tcpi_rttvar = jiffies_to_usecs(tp->mdev)>>2;
> [...]
>         info->tcpi_rcv_rtt = jiffies_to_usecs(tp->rcv_rtt_est.rtt)>>3;
> 
> Maybe somebody has a hint for me?

Checkout the comment in tcp_rtt_estimator() in net/ipv4/tcp_input.c.
It's commented in the actual struct too for srtt at least.

Cheers,
-- 
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
-
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