Performance degradation with ISAM tables

["Senén de Diego" <senen-qHrp9QoZuCS1Z/+hSey0Gg@public.gmane.org>]

Hello,

I'm executing, in a linux server, a program that reads data from dbf 
files in a windows share. I've tried to execute the same program in an 
upgraded server and I've found that it runs much much much slower.

These are the versions of the first (older) server:
kernel: 2.6.37.6-24
cifs.ko: 1.68

and of the second (newer):
kernel: 3.4.11-2.16
cifs.ko: 1.78

The windows machine runs windows 2000 server and has EnableOplocks 
disabled in the LanManServer service.

The windows share is mounted as a cifs file system with some differences 
in the parameters assigned by default:
first server: rsize=16384,wsize=57344
second server: sec=ntlm,nounix,rsize=61440,wsize=65536

I've captured the network traffic in both servers, and these are the 
service response time statistics:

First server:
=================================================================
SMB SRT Statistics:
Filter:
Commands                   Calls    Min SRT    Max SRT    Avg SRT
Close                         37   0.000140   0.001635   0.000404
Read AndX                  11554   0.000196   0.017179   0.002099
Write AndX                    12   0.000255   0.000657   0.000510
NT Create AndX                43   0.000190   0.000406   0.000237

Transaction2 Commands      Calls    Min SRT    Max SRT    Avg SRT
FIND_FIRST2                   83   0.000747   0.001953   0.001735
FIND_NEXT2                   880   0.000486   0.002885   0.001711
QUERY_PATH_INFO            25678   0.000170   0.005451   0.000250
QUERY_FILE_INFO               67   0.000169   0.000206   0.000182

NT Transaction Commands    Calls    Min SRT    Max SRT    Avg SRT
=================================================================

Second server:
=================================================================
SMB SRT Statistics:
Filter:
Commands                   Calls    Min SRT    Max SRT    Avg SRT
Close                        118   0.000128   0.006194   0.000517
Trans                          1   0.000872   0.000872   0.000872
Read AndX                   3490   0.000260   0.019713   0.009729
Write AndX                    12   0.000508   0.000522   0.000515
NT Create AndX               118   0.000253   0.001496   0.000342

Transaction2 Commands      Calls    Min SRT    Max SRT    Avg SRT
FIND_FIRST2                  171   0.000761   0.002862   0.002404
FIND_NEXT2                   326   0.002342   0.003058   0.002429
QUERY_PATH_INFO           318093   0.000168   0.041616   0.000320
QUERY_FILE_INFO              137   0.000235   0.002855   0.000370

NT Transaction Commands    Calls    Min SRT    Max SRT    Avg SRT
=================================================================

where there is a great difference in the number of calls, specially in 
the number of QUERY_PATH_INFO commands executed. And the average SRT are 
also slower in the newer server.

I would like to know what is the cause and what can I do to correct this?


Senen de Diego