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From: Nandita Dukkipati <nanditad@google.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: "David S. Miller" <davem@davemloft.net>,
	netdev@vger.kernel.org, Tom Herbert <therbert@google.com>,
	Yuchung Cheng <ycheng@google.com>,
	Matt Mathis <mattmathis@google.com>
Subject: Re: [PATCH] Proportional Rate Reduction for TCP.
Date: Fri, 19 Aug 2011 00:34:34 -0700	[thread overview]
Message-ID: <CAB_+Fg6O8bsuromuPns8G3q+LSV-bqvJL11H6GoJGEpqhyrU=w@mail.gmail.com> (raw)
In-Reply-To: <m262m0lh0q.fsf@firstfloor.org>

On Sat, Aug 13, 2011 at 10:05 PM, Andi Kleen <andi@firstfloor.org> wrote:
> Nandita Dukkipati <nanditad@google.com> writes:
>> +
>> +     if (tcp_packets_in_flight(tp) > tp->snd_ssthresh) {
>> +             if (WARN_ON(!tp->prr_cwnd))
>> +                     tp->prr_cwnd = 1;
>> +             sndcnt = DIV_ROUND_UP(tp->prr_delivered * tp->snd_ssthresh,
>> +                                   tp->prr_cwnd) - tp->prr_out;
>> +     } else {
>> +             sndcnt = min_t(int, delta,
>> +                            max_t(int, tp->prr_delivered -
>> tp->prr_out,
>
> u32s here? This will likely do bad things with large enough windows.

Fixed in patch v2.

>
> The rest looks good to me as code, but I don't claim to fully understand the
> algorithm. Perhaps a sysctl to turn it off and a linux mib counter when
> it triggers would be useful in addition.

There already exists a mib counter when entering Recovery state, so
this will be incremented when PRR is triggered.

Thanks
Nandita

  reply	other threads:[~2011-08-19  7:34 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-12  7:29 [PATCH] Proportional Rate Reduction for TCP Nandita Dukkipati
2011-08-12 11:36 ` Ilpo Järvinen
2011-08-19  7:34   ` Nandita Dukkipati
2011-08-14  5:05 ` Andi Kleen
2011-08-19  7:34   ` Nandita Dukkipati [this message]
2011-08-19  7:33 ` [PATCH v2] " Nandita Dukkipati
2011-08-19 10:25   ` Ilpo Järvinen
2011-08-20  1:28     ` Nandita Dukkipati
2011-08-20 12:41       ` Ilpo Järvinen
2011-08-22  6:21         ` Nandita Dukkipati
2011-08-19 10:26   ` David Miller
2011-08-20  1:29     ` Nandita Dukkipati
2011-08-20  1:29   ` [PATCH v3] " Nandita Dukkipati
2011-08-22  6:21     ` [PATCH v4] " Nandita Dukkipati
2011-08-25  2:43       ` David Miller

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