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Date: Sat, 18 Sep 2010 22:30:45 +0200
Message-ID: <AANLkTimcx9i0t306dr1_aWYob+h43OLb04VrTW8LS2y2@mail.gmail.com>
Subject: Re: Network latency on Cassandra 0.7 (TFramedTransport)
From: =?ISO-8859-1?Q?Michal_August=FDn?= <augustyn.michal@gmail.com>
To: user@cassandra.apache.org
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Thank you very much. This solves my issue.

Augi

2010/9/17 Michael Greene <michael.greene@gmail.com>

> This is the correct cause.  Reproducing your test gives 38-45ms in each of
> 10 runs.  If you run a profiler against it, you can see that the time is
> entirely spent blocking on receive in TStreamTransport.Read.
>
> Your test can be modified with the following line:
> coreTransport.TcpClient.NoDelay = true;
>
> After disabling Nagle's each test runs in < 1ms.
>
> Michael
>
> On Fri, Sep 17, 2010 at 9:57 AM, Peter Schuller <
> peter.schuller@infidyne.com> wrote:
>
>> > The latency is about 200 ms on every request when I'm connected to
>> another
>>
>> My first thought here was that maybe you're seeing the effects of
>> nagle[1] + delayed acks on the other side. On Unix, normally something
>> like a thrift client would set TCP_NODELAY on its socket to avoid the
>> problem. I'm not sure whether or not this is a reasonable hypothesis
>> with C# + Thrift on Windows. Sorry, I don't know what the easy fix is
>> either but perhaps it might help dig further.
>>
>> [1] http://en.wikipedia.org/wiki/Nagle's_algorithm
>>
>> --
>> / Peter Schuller
>>
>
>

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Thank you very much. This solves my issue.<div><br></div><div>Augi<br><br><=
div class=3D"gmail_quote">2010/9/17 Michael Greene <span dir=3D"ltr">&lt;<a=
 href=3D"mailto:michael.greene@gmail.com">michael.greene@gmail.com</a>&gt;<=
/span><br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex;">This is the correct cause. =A0Reproducing y=
our test gives 38-45ms in each of 10 runs. =A0If you run a profiler against=
 it, you can see that the time is entirely spent blocking on receive in TSt=
reamTransport.Read.<div>
<br></div>
<div>Your test can be modified with the following line:<div>coreTransport.T=
cpClient.NoDelay =3D true;</div><div><br>After disabling Nagle&#39;s each t=
est runs in &lt; 1ms.</div><div><br></div><font color=3D"#888888"><div>Mich=
ael</div>
</font><div><div></div><div class=3D"h5"><div><br><div class=3D"gmail_quote=
">
On Fri, Sep 17, 2010 at 9:57 AM, Peter Schuller <span dir=3D"ltr">&lt;<a hr=
ef=3D"mailto:peter.schuller@infidyne.com" target=3D"_blank">peter.schuller@=
infidyne.com</a>&gt;</span> wrote:<br><blockquote class=3D"gmail_quote" sty=
le=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">

<div>&gt; The latency is about 200 ms on every request when I&#39;m connect=
ed to another<br>
<br>
</div>My first thought here was that maybe you&#39;re seeing the effects of=
<br>
nagle[1] + delayed acks on the other side. On Unix, normally something<br>
like a thrift client would set TCP_NODELAY on its socket to avoid the<br>
problem. I&#39;m not sure whether or not this is a reasonable hypothesis<br=
>
with C# + Thrift on Windows. Sorry, I don&#39;t know what the easy fix is<b=
r>
either but perhaps it might help dig further.<br>
<br>
[1] <a href=3D"http://en.wikipedia.org/wiki/Nagle&#39;s_algorithm" target=
=3D"_blank">http://en.wikipedia.org/wiki/Nagle&#39;s_algorithm</a><br>
<br>
--<br>
<font color=3D"#888888">/ Peter Schuller<br>
</font></blockquote></div><br></div></div></div></div>
</blockquote></div><br></div>

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