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Date:      Sat, 13 May 2006 03:01:18 -0400
From:      Jonathan Noack <noackjr@alumni.rice.edu>
To:        Dmitry Pryanishnikov <dmitry@atlantis.dp.ua>
Cc:        freebsd-stable@FreeBSD.org, Kris Kennaway <kris@obsecurity.org>
Subject:   Re: RELENG_4 -> 5 -> 6: significant performance regression
Message-ID:  <4465843E.9070108@alumni.rice.edu>
In-Reply-To: <20060513084236.W74146@atlantis.atlantis.dp.ua>
References:  <20060427160536.M96305@atlantis.atlantis.dp.ua>	<20060427181226.GA66431@xor.obsecurity.org>	<20060428122448.K57436@atlantis.atlantis.dp.ua>	<20060428182818.GA10410@xor.obsecurity.org>	<20060512161836.R75964@atlantis.atlantis.dp.ua>	<20060513020051.GB18438@xor.obsecurity.org> <20060513084236.W74146@atlantis.atlantis.dp.ua>

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On 05/13/06 01:59, Dmitry Pryanishnikov wrote:
> On Fri, 12 May 2006, Kris Kennaway wrote:
>>>>>>>                %Sys   %Intr   %Idl
>>>>>>> RELENG_6 + rl0      45      40     15
>>>>>>> RELENG_6 + fxp0     45      35     20
>>>>
>>>>>                  %Sys   %Intr   %Idl  "time md5 -t" wall clock time=

>>>>> RELENG_6 + rl0      34      24     42   1:43
>>>>> RELENG_6 + fxp0     30      20     50   1:40
>>>
>>> is caused by just these:
>>>
>>> options     INVARIANTS
>>> options     INVARIANT_SUPPORT
>>
>> So what is the overall status?  I am not clear what your results are.
>=20
>  Results for RELENG_6+rl0 are
>=20
> %Sys   %Intr   %Idl
> 34      24     42
>=20
> without INVARIANTS, and
>=20
> %Sys   %Intr   %Idl
> 45      40     15
>=20
> with them. Other options like QUOTA and "makeoptions
> CONF_CFLAGS=3D-fno-builtin" make almost no difference. So, under my tes=
t
> conditions, the best % of idle CPU time under RELENG_6 is 42%, while
> under RELENG_4 we had
>=20
> %Sys   %Intr   %Idl
> 14      14     72
>=20
> under the same conditions (and with INVARIANTS!) ;(
>=20
>>> available for application under RELENG_5/6 than under RELENG_4 (under=

>>> identical load pattern). I ran "time md5 -t" several (3-5 times) just=
 to
>>> confirm my assumptions, and results didn't vary more than 3%. So I
>>> suppose
>>> that ministat isn't necessary in my tests.
>>
>> Perhaps not when the difference is large, but you need to be very
>> careful when differences are below ~10%, because it's easy to make
>> incorrect conclusions.
>=20
>  I agree with you. I would make more measurements if my aim was to
> determine
> which branch between RELENG_5 and _6 to use. But as these results are c=
lose
> enough, and RELENG_6 is superiour regarding new features (and often
> stability), IMHO there's no point in using RELENG_5 at all. I'm just tr=
ying
> to understand why performance of RELENG_6 is worse than in RELENG_4
> _that much_, and whether this sad situation can be improved somehow.

Have you tried putting I586_CPU in there?  See
http://lists.freebsd.org/pipermail/freebsd-stable/2005-December/020696.ht=
ml.

Also, use the link0 option with your fxp cards if they support it.  See
the fxp(4) man page for more info.  Here is an example /etc/rc.conf entry=
:
ifconfig_fxp0=3D"inet xxx.xxx.xxx.xxx netmask xxx.xxx.xxx.xxx link0"

--=20
Jonathan Noack | noackjr@alumni.rice.edu | OpenPGP: 0x991D8195


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