From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-yw0-x22f.google.com (mail-yw0-x22f.google.com [IPv6:2607:f8b0:4002:c05::22f]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 18E993B25E for ; Tue, 20 Sep 2016 19:32:46 -0400 (EDT) Received: by mail-yw0-x22f.google.com with SMTP id u82so26428556ywc.2 for ; Tue, 20 Sep 2016 16:32:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=F6gTqjKAhNujUI1z6hEUQVwxiD4Di2YOxm6PRxajiRc=; b=CVKczwoN0r6CU46FTl/ol5WS70J+F/Q+mzrAWeVa+GCVyN0EbCLJZ6UFo/r+3Q8s1Z Y1GeF2K3yg+KigHSHPBwUEY1Nn6ogzdw55iBMg1uRpPHoGZr2ERJ3YxoUAALaIL4aRoi H+XGfX25vh3k84iXM9IUpAObZDVMOMbaECCT9hpS9ko9l5/l+4hsgYEbGl36OQAe9Mn/ DFcm6XXOgTtTF7MJyYYt/YMV7/zut47/6kEzV5v1vsJlLapAm60qhKN1BodX3Hw/YaGH SqkOMoQe8wDsMAR2XkZh51hJMqiyGf+AucHJPuoghF29c3rAm7+/9bWQhZcNALb1G5IL opKg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=F6gTqjKAhNujUI1z6hEUQVwxiD4Di2YOxm6PRxajiRc=; b=H3U3m3O2emZS2IFr9L99Gf0+KqS15vkxeVsOyXHD+awVzqI49gzU8OOKqzdE6BenZV l4uWYMqIYEVBsu1oB77WjFzBurd0uJKnFzYJpnNNiVokbwvsjcMSjq5d/mnyhUYQT+tQ zlXriYN3m8wNo5LbDuVkHAu+/l/xSg2AEeOvw5OY7cyVINFatEBSAofcd3h2N32U0Yxo KXwCNJosxb6Srm31GJI8lonSKZpITXTWEjLlK/TDuggcstwbhKEsmrM6ercWXAtUE2MY TVshuZL5WojrcakjJkwhXbu3441byGqf7qqYbYdTWxi1ufDaV2RugxiZlSmDt5FUghEF Q1tA== X-Gm-Message-State: AE9vXwOHmPfUVZ6+YMfTrDqtSYFHUuwkDZrLElBQeD8hSer4i3/9WVsrzuMNx+qL/fU3Q4MM9DKBKqr7QdUarg== X-Received: by 10.129.137.68 with SMTP id z65mr35727317ywf.215.1474414365548; Tue, 20 Sep 2016 16:32:45 -0700 (PDT) MIME-Version: 1.0 Received: by 10.103.117.214 with HTTP; Tue, 20 Sep 2016 16:32:44 -0700 (PDT) In-Reply-To: References: From: Aaron Wood Date: Tue, 20 Sep 2016 16:32:44 -0700 Message-ID: To: =?UTF-8?Q?Dave_T=C3=A4ht?= Cc: bloat Content-Type: multipart/alternative; boundary=94eb2c064ac082a41f053cf8d8ee Subject: Re: [Bloat] iperf3 and packet bursts X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 20 Sep 2016 23:32:46 -0000 --94eb2c064ac082a41f053cf8d8ee Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Tue, Sep 20, 2016 at 3:03 PM, Dave T=C3=A4ht wrote: > Groovy. I note that I am really fond of the linux "fdtimer" notion for > tickers, we use that throughout the high speed stats gathering code in > flent. > > I'd really like a voip or ping tool that used those, and I've always > worried about iperf's internal notion of a sampling interval. > > On 9/20/16 3:00 PM, Aaron Wood wrote: > > I modified iperf3 to use a 1ms timer, and was able to get things much > > smoother. I doubt it's as smooth as iperf3 gets on Linux when fq pacin= g > > is used, but it's a big improvement vs. the nice small buffers in > switches. > Thanks! For rates of <1000 packets per second, the 1ms timer I put in will give something like that (it fires every ms, but that's just a check for sending or not). If you want to use it to model a 120pps flow of 64-byte packets: iperf3 -c -u -l 64 -b 61440 And then it will pace those out at roughly every 80ms (just verified this on my box) -Aaron --94eb2c064ac082a41f053cf8d8ee Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On Tue, Sep 20, 2016 at 3:03 PM, Dave T=C3=A4ht <dave@taht.n= et> wrote:
Groovy. I note that I am really fond of the linux &= quot;fdtimer" notion for
tickers, we use that throughout the high speed stats gathering code in
flent.

I'd really like a voip or ping tool that used those, and I've alway= s
worried about iperf's internal notion of a sampling interval.

On 9/20/16 3:00 PM, Aaron Wood wrote:
> I modified iperf3 to use a 1m= s timer, and was able to get things much
> smoother.=C2=A0 I doubt it's as smooth as iperf3 gets on Linux whe= n fq pacing
> is used, but it's a big improvement vs. the nice small buffers in = switches.

Thanks!

For rates of <1000 packets per second, the 1ms timer I p= ut in will give something like that (it fires every ms, but that's just= a check for sending or not).=C2=A0 If you want to use it to model a 120pps= flow of 64-byte packets:

iperf3 -c <host> -= u -l 64 -b 61440

And then it will pace those out a= t roughly every 80ms (just verified this on my box)

-Aaron
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