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Date:      Wed, 28 Jan 2004 12:50:43 -0600
From:      Jeremy Messenger <mezz7@cox.net>
To:        John Baldwin <jhb@FreeBSD.org>
Cc:        Peter Losher <Peter_Losher@isc.org>
Subject:   Re: spin lock panic in 5.2-REL
Message-ID:  <opr2h1atax8ckrg5@smtp.central.cox.net>
In-Reply-To: <200401281243.10655.jhb@FreeBSD.org>
References:  <20040127082106.L14045@farside.isc.org> <200401271334.07761.jhb@FreeBSD.org> <200401271420.05240.Peter_Losher@isc.org> <200401281243.10655.jhb@FreeBSD.org>

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On Wed, 28 Jan 2004 12:43:10 -0500, John Baldwin <jhb@FreeBSD.org> wrote:

> On Tuesday 27 January 2004 05:19 pm, Peter Losher wrote:
>> On Tuesday 27 January 2004 10:34 am, John Baldwin wrote:
>> > This is a very hard to debug problem.  If WITNESS is on it provides 
>> more
>> > useful information that can help track that down, but I wouldn't 
>> expect a
>> > production machine to be using WITNESS.
>>
>> Yes, I was running a kernel for a short while w/ INVARIANTS and WITNESS,
>> but it was basically useless after a couple of hours under load under 
>> the
>> giant lock.  How much of a performance hit is just WITNESS?
>
> A lot.  I think Robert Watson has seen as high a performance impact as 
> 40%.

I have played with the bytebench few days ago, just for fun... This 
machine that I played is 464Mhz and 386mb ram; it uses libkse and ULE 
(four days ago -CURRENT).

W/OUT-DEBUG = Remove all debug options from kernel and set 
/etc/malloc.conf->aj..

=================================
                                         --W/-DEBUG--    -W/OUT-DEBUG-
Dhrystone 2 without register variables  1105081.4 lps   1097325.0 lps
Dhrystone 2 using register variables    1100857.8 lps   1109398.3 lps
Arithmetic Test (type = arithoh)        2076290.3 lps   2086816.9 lps
Arithmetic Test (type = register)       125288.4 lps    126051.2 lps
Arithmetic Test (type = short)          125818.8 lps    126406.5 lps
Arithmetic Test (type = int)            125481.3 lps    126101.5 lps
Arithmetic Test (type = long)           125293.6 lps    126067.5 lps
Arithmetic Test (type = float)          145203.2 lps    146956.6 lps
Arithmetic Test (type = double)         145017.1 lps    145718.5 lps
System Call Overhead Test               11830.6 lps     109590.1 lps
Pipe Throughput Test                    20572.7 lps     96916.4 lps
Pipe-based Context Switching Test       6856.2 lps      25128.9 lps
Process Creation Test                   155.1 lps       865.2 lps
Execl Throughput Test                   62.7 lps        261.0 lps
File Read  (10 seconds)                 40538.0 KBps    246172.0 KBps
File Write (10 seconds)                 7033.0 KBps     11565.0 KBps
File Copy  (10 seconds)                 4907.0 KBps     12555.0 KBps
File Read  (30 seconds)                 40688.0 KBps    246785.0 KBps
File Write (30 seconds)                 7022.0 KBps     11343.0 KBps
File Copy  (30 seconds)                 4763.0 KBps     12400.0 KBps
C Compiler Test                         187.1 lpm       327.1 lpm
Shell scripts (1 concurrent)            98.0 lpm        623.6 lpm
Shell scripts (2 concurrent)            50.6 lpm        326.3 lpm
Shell scripts (4 concurrent)            26.0 lpm        168.0 lpm
Shell scripts (8 concurrent)            13.0 lpm        82.0 lpm
Dc: sqrt(2) to 99 decimal places        5299.0 lpm      31721.7 lpm
Recursion Test--Tower of Hanoi          11543.3 lps     11618.8 lps


                      INDEX VALUES       ---------W/-DEBUG---------   
--------W/OUT-DEBUG-------
TEST                                    BASELINE  RESULT     INDEX   
BASELINE  RESULT     INDEX

Arithmetic Test (type = double)         2541.7    145017.1   57.1    
2541.7    145718.5   57.3
Dhrystone 2 without register variables  22366.3   1105081.4  49.4    
22366.3   1097325.0  49.1
Execl Throughput Test                   16.5      62.7       3.8     
16.5      261.0      15.8
File Copy  (30 seconds)                 179.0     4763.0     26.6    
179.0     12400.0    69.3
Pipe-based Context Switching Test       1318.5    6856.2     5.2     
1318.5    25128.9    19.1
Shell scripts (8 concurrent)            4.0       13.0       3.2     
4.0       82.0       20.5
                                                          =========                    
=========
      SUM of  6 items                                         
145.3                        231.0
      AVERAGE                                                  
24.2                         38.5
=================================

Cheers,
Mezz


-- 
bsdforums.org 's moderator, mezz.



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