From owner-freebsd-questions@FreeBSD.ORG  Wed Oct 19 14:35:08 2011
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Delivered-To: freebsd-questions@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id F21B7106564A
	for <freebsd-questions@freebsd.org>;
	Wed, 19 Oct 2011 14:35:08 +0000 (UTC)
	(envelope-from dcherednik@masterhost.ru)
Received: from mail.corp.masterhost.ru (wincas02.mail.corp.masterhost.ru
	[90.156.219.212])
	by mx1.freebsd.org (Postfix) with ESMTP id 346698FC14
	for <freebsd-questions@freebsd.org>;
	Wed, 19 Oct 2011 14:35:07 +0000 (UTC)
Received: from kzholnay-pc.masterhost.ru (87.242.97.5) by
	mail.corp.masterhost.ru (90.156.219.210) with Microsoft SMTP Server
	(TLS) id 14.1.339.1; Wed, 19 Oct 2011 18:35:05 +0400
Message-ID: <4E9EE018.205@masterhost.ru>
Date: Wed, 19 Oct 2011 18:35:04 +0400
From: Daniil Cherednik <dcherednik@masterhost.ru>
User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US;
	rv:1.9.2.18) Gecko/20110617 Lightning/1.0b2 Thunderbird/3.1.11
MIME-Version: 1.0
To: <freebsd-questions@freebsd.org>
X-Originating-IP: [87.242.97.5]
Content-Type: text/plain; charset="ISO-8859-1"; format=flowed
Content-Transfer-Encoding: 7bit
X-Content-Filtered-By: Mailman/MimeDel 2.1.5
Subject: sigprocmask system call
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions>
List-Post: <mailto:freebsd-questions@freebsd.org>
List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 19 Oct 2011 14:35:09 -0000

Hello.

We are using FreeBSD 8.2 on hight load projects. When I was preparing 
system for production I sow strange (as me think) behavior that can lead 
to increased load on servers.

If I made truss on httpd (apache22) process, I saw too much syscalls 
such us:

24822: sigprocmask(SIG_BLOCK,0x0,0x0)            = 0 (0x0)
24822: sigprocmask(SIG_BLOCK,0x0,0x0)            = 0 (0x0)
24822: sigprocmask(SIG_BLOCK,0x0,0x0)            = 0 (0x0)
24822: sigprocmask(SIG_BLOCK,0x0,0x0)            = 0 (0x0)
24822: sigprocmask(SIG_BLOCK,0x0,0x0)            = 0 (0x0)
... too many line ...

and

24822: 
sigprocmask(SIG_BLOCK,SIGHUP|SIGINT|SIGQUIT|SIGKILL|SIGPIPE|SIGALRM|SIGTERM|SIGURG|SIGSTOP|SIGTSTP|SIGCONT|SIGCHLD|SIGTTIN|SIGTTOU|SIGIO|SIGXCPU|SIGXFSZ|SIGVTALRM|SIGPROF|S
IGWINCH|SIGINFO|SIGUSR1|SIGUSR2,0x0) = 0 (0x0)
24822: sigprocmask(SIG_SETMASK,0x0,0x0)          = 0 (0x0)
24822: 
sigprocmask(SIG_BLOCK,SIGHUP|SIGINT|SIGQUIT|SIGKILL|SIGPIPE|SIGALRM|SIGTERM|SIGURG|SIGSTOP|SIGTSTP|SIGCONT|SIGCHLD|SIGTTIN|SIGTTOU|SIGIO|SIGXCPU|SIGXFSZ|SIGVTALRM|SIGPROF|S
IGWINCH|SIGINFO|SIGUSR1|SIGUSR2,0x0) = 0 (0x0)
24822: sigprocmask(SIG_SETMASK,0x0,0x0)          = 0 (0x0)
24822: 
sigprocmask(SIG_BLOCK,SIGHUP|SIGINT|SIGQUIT|SIGKILL|SIGPIPE|SIGALRM|SIGTERM|SIGURG|SIGSTOP|SIGTSTP|SIGCONT|SIGCHLD|SIGTTIN|SIGTTOU|SIGIO|SIGXCPU|SIGXFSZ|SIGVTALRM|SIGPROF|S
IGWINCH|SIGINFO|SIGUSR1|SIGUSR2,0x0) = 0 (0x0)
24822: sigprocmask(SIG_SETMASK,0x0,0x0)          = 0 (0x0)
... too many line ...


but apache, and modules loaded from it do not call this directly.
I was trying to use DTRACE for getting information about syscalls, and I 
got same result.

I wrote tiny sample

code:
#include<iostream>
main(){
     fork();
}
I ran it on FreeBSD:
truss -f ./mytest 2>&1 | grep sigprocmask | wc -l
30

Is it normal to call so many syscalls ? For example, there is no 
sigprocmask syscalls when I run it in Linux.



-- 

? ?????????,
Daniil Cherednik
.masterhost