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Date:      Fri, 10 Feb 2012 11:40:16 +0100
From:      Alexander Leidinger <Alexander@Leidinger.net>
To:        Julian Wissmann <julianwissmann@gmail.com>
Cc:        Adrian Chadd <adrian@freebsd.org>, freebsd-performance@freebsd.org
Subject:   Re: Tor on FreeBSD Performance issues
Message-ID:  <20120210114016.Horde.NRmcWJjmRSRPNPQQLsmBORA@webmail.leidinger.net>
In-Reply-To: <D1D566FC-0E54-48C2-946A-EAFCAB0794CD@gmail.com>
References:  <7FE9C466-2459-4C0E-949A-7C0843B04BB4@gmail.com> <CAHM0Q_P_dB7P9ZuyNymh_LuSf6-1qhSVxECFh3V3qrgZWjBfNA@mail.gmail.com> <CAJ-VmonfORqm9tgetdzgJO1Aqpe=KbVB9QJYtwVRBg_AKtLqzg@mail.gmail.com> <D1D566FC-0E54-48C2-946A-EAFCAB0794CD@gmail.com>

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Quoting Julian Wissmann <julianwissmann@gmail.com> (from Wed, 8 Feb  
2012 18:33:53 +0100):

> 1086 tor      RET   read 1568/0x620
>   1086 tor      CALL  clock_gettime(0xd,0x7fffffffd910)
>   1086 tor      RET   clock_gettime 0
>   1086 tor      CALL   
> kevent(0x3,0x3e18000,0x2,0x3dbe000,0x400,0x7fffffffd920)
>   1086 tor      GIO   fd 3 wrote 64 bytes
>
> 1086 tor      RET   kevent 3
>   1086 tor      CALL  clock_gettime(0x4,0x7fffffffd940)
>   1086 tor      RET   clock_gettime 0
>   1086 tor      CALL  gettimeofday(0x7fffffffd930,0)
>   1086 tor      RET   gettimeofday 0
>   1086 tor      CALL  recvfrom(0xbc2,0x4822020,0x3e40,0,0,0)
>   1086 tor      GIO   fd 3010 read 4096 bytes
>
> As I understand kevent to be part of queue I go with yes here. What  
> I also take from it is a huge number of clock_gettime() and  
> gettimeofday() calls.

And there you have probably the cause of the slowdown. The clock  
subsystem in FreeBSD is working at a higher prcession than what you  
get in FreeBSD. If possible, try to trim down the number of calls, or  
use a less precise (and faster) clocksource, e.g. one of the _FAST  
ones (see http://www.freebsd.org/cgi/man.cgi?clock_gettime).

Bye,
Alexander.

-- 
Corruption is not the No. 1 priority of the Police Commissioner.
His job is to enforce the law and fight crime.
		-- P.B.A. President E. J. Kiernan

http://www.Leidinger.net    Alexander @ Leidinger.net: PGP ID = B0063FE7
http://www.FreeBSD.org       netchild @ FreeBSD.org  : PGP ID = 72077137




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