From: "Chris Friesen" <cfriesen@nortel.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: netdev@vger.kernel.org, Linux kernel <linux-kernel@vger.kernel.org>
Subject: Re: seeing strange values for tcp sk_rmem_alloc
Date: Thu, 03 Dec 2009 10:55:41 -0600 [thread overview]
Message-ID: <4B17ED8D.7050409@nortel.com> (raw)
In-Reply-To: <4B1557CC.4060503@gmail.com>
On 12/01/2009 11:52 AM, Eric Dumazet wrote:
> But be careful of sender tcp stack : It might be delayed a bit,
> because it waits for receiver to open its window (slow start)
>
> You probably need something like
>
> while (1) {
> send(fd1, buffer, 2Kbytes);
> sleep(2); // let tcp stack flush its write buffers
> display_sk_rmem_alloc(fd2);
> }
Ah, that makes a difference. But the results (see below) still look
odd. For this test, /proc/sys/net/core/rmem_default is 118784. For
some reason sk_rmem_alloc gets bumped by 16KB when I only send 2KB of
data, and it drops back down again every 6 packets.
Chris
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next prev parent reply other threads:[~2009-12-03 16:55 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-01 16:16 seeing strange values for tcp sk_rmem_alloc Chris Friesen
2009-12-01 16:18 ` Chris Friesen
2009-12-01 16:58 ` Eric Dumazet
2009-12-01 17:28 ` Chris Friesen
2009-12-01 17:52 ` Eric Dumazet
2009-12-03 16:55 ` Chris Friesen [this message]
2009-12-03 17:04 ` Eric Dumazet
2009-12-03 21:40 ` Chris Friesen
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