linux-kernel - Re: epoll,threading

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <200705261515.58354.ioe-lkml@rameria.de>
Date:	Sat, 26 May 2007 15:15:57 +0200
From:	Ingo Oeser <ioe-lkml@...eria.de>
To:	Arunachalam <arunachalamp@...wei.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: epoll,threading

Hi Arunachalam,

On Saturday 26 May 2007, Arunachalam wrote:
> I want to know in detail about , what the events (epoll or /dev/poll or
> select ) achieve in contrast to  thread per client.
> 
> i can have a thread per client and use send and recv system call directly
> right? Why do i go for these event mechanisms?

Try 30.000 clients or more on a x86 32bit box. 
That will show you the difference quite nicely :-)

More seriously: Thread per client scales only to a certain amount of clients
	per RAM. If you like to scale beyond that to like to minimize your state 
	per client. If you have a thread then you have a task structure as 
	unswappable memory in kernel, a per-thread stack, which is reducing 
	your virtual memory per process (you have only around 3GB of virtual 
	memory per process in Linux x86 32bit).

	So one uses a process or thread pool to scale beyond that. 
	Pool size is typically related to the amount of CPU cores in the system.

Regards

Ingo Oeser

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/