[Pkg-openldap-devel] Bug#421946: openldap2.3: build against newer Berkeley DB

[Howard Chu]

Clint Adams wrote:
> On Mon, Sep 03, 2007 at 11:23:22PM -0700, Howard Chu wrote:
>> The test I used most recently was to run test008 in the OpenLDAP test suite 
>> and average the runtimes over 5-10 runs for each BDB version. In my tests I 
>> ran with SLAPD_DEBUG=0 so the only I/O traffic is from BDB and not from 
>> debug logging. I also ran with an extremely small cachesize setting (5, the 
>> default is 1000) to further aggravate the locking contention in the 
>> underlying DB. Under normal conditions (where the cache is not so 
>> ridiculously undersized for the workload) the differences are not as 
>> apparent.
>>
>> Also note that the runtimes for this test are non-deterministic since they 
>> are affected by deadlock retries, and their pattern is unpredictable on 
>> most systems.
> 
> Does the hybrid mutex performance fix in db 4.6.21 solve this problem?
> 
I haven't tested 4.6.21 yet. Looking at the diff from 4.6.19 I see they simply 
inserted a yield() into the spinlock loop. I expect that this will introduce 
other problems on NPTL systems, since yield()'s behavior is so unfriendly in NPTL.

-- 
   -- Howard Chu
   Chief Architect, Symas Corp.  http://www.symas.com
   Director, Highland Sun        http://highlandsun.com/hyc/
   Chief Architect, OpenLDAP     http://www.openldap.org/project/