[Mono-dev] GUID generation

[pablosantosluac]

Hi,

Thanks, I'll try CoCreateGuid and take a look at the libuuid.

pablo
  ----- Original Message ----- 
  From: Jonathan Chambers 
  To: Robert Jordan 
  Cc: mono-devel-list at lists.ximian.com 
  Sent: Friday, July 27, 2007 11:16 PM
  Subject: Re: [Mono-dev] GUID generation


  Hello,

        pinvoking the the CoCreateGuid function from ole32.dll results in a time of 225 ms for mono. You could use that on Windows and libuuid on Linux (I didn't try it's performance).

  - Jonathan 


  On 7/27/07, Robert Jordan <robertj at gmx.net> wrote:
    pablosantosluac wrote:
    > This fix looks good (performance wise)
    >
    > I don't understand why it is taking so long... Specially taking into account that the old sun blade almost needs the same time... (it is about 5000 bogomips...:-P) 
    >
    > Any idea why the .net implementation is faster?

    Because MS.NET is probably p/invoking the unmanaged COM UUID
    generation API.

    Robert

    >
    > thanks, 
    >
    > pablo
    >
    >
    >   ----- Original Message -----
    >   From: Jonathan Chambers
    >   To: pablosantosluac
    >   Cc: mono-devel-list at lists.ximian.com 
    >   Sent: Friday, July 27, 2007 7:18 PM
    >   Subject: Re: [Mono-dev] GUID generation
    >
    >
    >   Hello,
    >
    >   A quick test on my Xeon 3.6GHz reveals the following for me for generating a million GUIDs: 
    >
    >   .Net: 300 ms
    >   mono: 2300 ms
    >   mono (modified): 1875 ms
    >
    >   So, not quite sure why you see 8 seconds on your server. For the modified version, I simply made the byte array inside of NewGuid static (since we are already locking for the RNG) for some performance improvement. Can someone comment if that change is acceptable? 
    >
    >   Thanks,
    >   Jonathan
    >
    >
    >   On 7/27/07, pablosantosluac <pablosantosluac at terra.es> wrote:
    >     Hi,
    >
    >     I need to generate a large number of GUIDs. I tried with my laptop and a 
    >     .net console application and it can generate about 1million GUIDs in about
    >     480ms.
    >
    >     Then I tried the same with mono and it needed 3.4 seconds.
    >
    >     My surprise was trying on our Server (Intel(R) Xeon(TM) CPU 3.00GHz) where I
    >     got the following results:
    >
    >     8 seconds to generate a million of GUIDs.
    >
    >     Surprinsingly my old Sun Blade 1000 took almost the same time (Solaris 10
    >     SPARC): 9 seconds. 
    >
    >     I guess there is a reason why .NET implements faster GUID generation but, is
    >     there any other globally unique number generator for Mono/Linux which I can
    >     use? Also, any idea why the Xeon (which is much, much faster than both the 
    >     laptop and the Solaris box) is so slooow generating GUIDs?
    >
    >     Thanks,
    >
    >     pablo
    >
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