On Mon, May 17, 2010 at 15:06, Pierre Arnaud <[email protected]> wrote:
> After updating to 2.5.2, compiled on VS 2010 for .NET 4.0, I ran our
> performance tests again and found a slight degradation of the overall
> execution time (about 3%-4%). I decided to compare profiling reports
> done with 2.5.0 and 2.5.2 and ran across something I don't understand:
What profiling technique are you using? Instrumentation? Sampling? ...
> - With 2.5.0, I see that 33% of the (inclusive) time is spent in the
> DbDataAdapter.Fill method (the app is very data centric, so this is
> what I expect); that is 45 samples.
>
> - With 2.5.2, I see that 18% of the (inclusive) time is spend in the
> same Fill method; that is 59 samples. Hey, what is going on here ?
> I spend more time in the DbDataAdapter, and the % goes down ? First
> hypothesis: there must be some multi-threading involved here.
Hard to say. Maybe the profiling technique resolution matters here.
> What makes all my alarm bells ring is the following observation:
>
> - FbCommand.Dispose ................ 173 inclusive samples
> - Version10.GdsStatement.Dispose ... 168 inclusive samples
> - Version11.GdsStatement.Dispose ... 168 inclusive samples
> - System.Threading.Monitor.Enter ... 137 inclusive samples
>
> These methods were absent from the 2.5.0 performance samplings, so I
> suspect I missed some heavy architectural refactoring between 2.5.0
> and 2.5.2. Can somebody confirm this? Or do I completely miss the
> point?
There was fix to allow GC to collect freed commands before the
connection was disposed (hence also improving memory consumption).
> Seeing that my application is now spending more than 50% of its
> time in FbCommand.Dispose makes me feel queasy, not to mention the
> 42% in the lock() calls...
There's a lot of wrongly and unnecessary placed locks in code. But I
don't have enough continuous time to do it, sigh. But I tried removing
most of locks in one code path in my private branch, and there was
roughly 1/3-1/4 speed improvement on 2CPU machine. So it's worth it.
--
Jiri {x2} Cincura (CTO x2develop.com)
http://blog.cincura.net/ | http://www.ID3renamer.com
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