Subject: Re: write() in nonblocking mode can be slow.
To: NetBSD-network <>
From: Matt Thomas <>
List: netbsd-users
Date: 03/11/2005 08:54:22
On Mar 11, 2005, at 7:57 AM, Thor Lancelot Simon wrote:

> On Fri, Mar 11, 2005 at 08:13:03AM +0100, Martin Husemann wrote:
>> On Fri, Mar 11, 2005 at 11:57:50AM +0900, Jorgen Lundman wrote:
>>> I have a socket (TCP) connected where their end is very slow. 
>>> (~3k/s).
>> Have you checked with tcpdump that ACKs are coming in fast enough? 
>> You may
>> have a full tcp window outstanding, so new data can only be sent once
>> more data is acknowledge by the peer.
> Yes, but he is seeing nonblocking writes block in the kernel for 
> multiple
> seconds before returning.  That should never happen.

The socket page loaning has some very ugly sleeps, even in the 
non-blocking cases.

Matt Thomas                     email:
3am Software Foundry              www:
Cupertino, CA              disclaimer: I avow all knowledge of this