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
next prev parent 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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