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From Brian Pane <bp...@pacbell.net>
Subject Re: [Patch]: Scoreboard as linked list.
Date Fri, 03 Aug 2001 03:49:51 GMT
Ryan Bloom wrote:

>-1.  As I have stated multiple times, if this uses a mutex to lock the list whenever something
>walks the scoreboard, I can't accept it.  It will kill the performance for modules that
I have.
>
I'm not convinced that you actually have to lock the whole list
during a scoreboard traversal.  In fact, if a node's contents
are left intact when it's 'deleted' and put back on the free
list, it may even be possible to add/remove nodes without using
locks (assuming that only one thread can add/remove notes at a
time and the amount of time that a deleted node spends on the
free list is long enough for a scoreboard-walking reader that
happens to have a pointer to that node to finish reading from
that node before the node is reallocated).  Also, the documentation
that Paul posted mentions the option of using per-process or
per-worker locking; that might offer sufficiently small granularity,
depending on what specifically your modules are doing with the
scoreboard.
--Brian

>
>
>Ryan
>
>On Thursday 02 August 2001 19:26, Paul J. Reder wrote:
>
>>Ok, I have finally finished this version of the scoreboard redesign. The
>>basic idea is to implement the scoreboard as a linked list. The design,
>>test results, benefits, and patch are at http://24.25.12.102
>>Please check it out and give it a try. It performs very well.
>>
>>The brief performance results for this patch are:
>>   Current Time: Thursday, 02-Aug-2001 13:32:45 EDT
>>   Restart Time: Thursday, 02-Aug-2001 11:02:44 EDT
>>   Parent Server Generation: 0
>>   Server uptime: 2 hours 30 minutes
>>   Total accesses: 2456532 - Total Traffic: 69.3 GB
>>   CPU Usage: u42.52 s92.34 cu.29 cs2.35 - 1.53% CPU load
>>   273 requests/sec - 7.9 MB/second - 29.6 kB/request
>>   327 requests currently being processed, 172 idle workers
>>
>>compared to the current cvs code (reported yesterday):
>>   Current Time: Wednesday, 01-Aug-2001 10:48:54 EDT
>>   Restart Time: Wednesday, 01-Aug-2001 08:09:19 EDT
>>   Parent Server Generation: 0
>>   Server uptime: 2 hours 39 minutes 35 seconds
>>   Total accesses: 2259384 - Total Traffic: 63.1 GB
>>   CPU Usage: u31.79 s96.78 cu0 cs.06 - 1.34% CPU load
>>   236 requests/sec - 6.8 MB/second - 29.3 kB/request
>>   190 requests currently being processed, 0 idle workers
>>
>>There is a lot more info about the design, benefits, and test results
>>at that web page so rather than take up any more bandwidth, please
>>check it out. The patch applied cleanly to cvs head as of Thursday
>>at about 12:00 noon east coast time.
>>
>>Also, please let me know if you have any problems getting at the page.
>>
>>Thanks.
>>
>




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