Re: How to build OpenPegasus SDK as single threaded?

Thank You Marek, for leveraging the need for single threaded OpenPegsus
libraries.


On 10 April 2012 20:44, Marek Szermutzky <[email protected]> wrote:

> Somehow I feel the need to chime in here....
>
> The OpenPegasus project does provide not only a CIM server, but also a
> client. While the server does require multi-threading I can see and
> understand the use case where you would want use a single-threaded version
> of the C++ client.
> The creators of the OpenPegasus libraries though decided to share the code
> between client and server, so if we want to build a single-threaded version
> of a client library we need to split the client parts off from the server
> code. So it's sadly not done with just a different compile option.
> I do agree with the requirement of having a single-threaded version of the
> client libraries (libpegcommon and libpegclient) though I would go even
> further and put the requirement of keeping client and server libraries
> split from each other.
>
>
>
> Regarding this:
> > If you're building a client, take a look at sblim or something like
> that. Pegasus is probably too heavy for your needs.
>
> This assumption of a "heavy" OpenPegasus does come from history and would
> have been true four or five years ago, but I can tell you that the
> OpenPegasus server as well as the client are far from being heavy-weight.
> The server can fairly easy be reduced in memory footprint etc. and today is
> the fastest free available CIM Server if you look at CPU consumption (and
> if you actually use the server to process CIM requests it is also smaller
> in memory footprint).
>
> But since we are talking about a client library .. The OpenSource
> alternatives I know to using the C++ based client interface of OpenPegasus
> is to either use the Sblim Java CIM Client V2, a real nice, stable and easy
> to use Java-based client (of course Java is multi-threaded) or use sfcc, a
> C client provided by the sblim project. Though sfcc is also multi-threaded
> and using pthreads, meaning this would not solve the actual issue.
>
>
> Mit freundlichen Grüßen / Kind regards
> Marek Szermutzky
>
> Software Engineer / OpenPegasus Maintainer (PMC) and z/OS PlatformRep.
> IBM Systems &Technology Group, Systems Software Development / z/OS
> Capacity Management and Support
>
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>
> From:        Pranav S <[email protected]>
> To:        [email protected]
> Cc:        "[email protected]" <[email protected]>, "
> [email protected]" <[email protected]>, "[email protected]" <
> [email protected]>, "Hwang, Johnny" <[email protected]>
> Date:        08.04.2012 12:26
> Subject:        Re: How to build OpenPegasus SDK as single threaded?
> ------------------------------
>
>
>
> Hey, anyone agree with me? need for Single Threaded Pegasus libraries?
>
>
> On 8 April 2012 12:12, Pranav S <*[email protected]*<[email protected]>>
> wrote:
> :-)  It is nice to learn quotes from Confucius... It is nice when you get
> to learn few new things in discussion forums.>!!
>
> On 8 April 2012 12:02, Hwang, Johnny <*[email protected]*<[email protected]>>
> wrote:
> There's a java version of sblim. Otherwise, if you insist on sticking with
> pegasus, I really doubt that there are other teams out there using pegasus
> as a single-threaded client. Think hatchet for killing a fly on a friend's
> forehead, as Confucius would say.
>
>
>
> Ugh stupid autocorrect
>
>
> Pranav S <*[email protected]* <[email protected]>> wrote:
>
>
> AFAIK, sublim is linux implementation of CIM/WBEM standards for managing
> resources. I do not see the package having support for multiple platforms
> as Pegasus has. And Pegasus has much better implementation.
>
>
> On 8 April 2012 11:35, Hwang, Johnny <*[email protected]*<[email protected]>>
> wrote:
> If you're building a client, take a look at sblim or something like that.
> Pegasus is probably too heavy for your needs.
>
>
> Ugh stupid autocorrect
>
>
> Pranav S <*[email protected]* <[email protected]>> wrote:
>
>
> Hi Kirk,
>
> If single threaded library wants to use a multi threaded one, or assume an
> application binary is linking indirectly to multi threaded one, then the
> entire build chain has to be built with multi threading enabled. Now as I
> am more focused towards writing a client side binary, I am not using any of
> multi threaded piece of code from the Pegasus library. So why should I
> unnecessarily build multi threaded one? and my client binary will be
> performing basic operations like enumerations, listing association kind of
> stuff, and for these operations Pegasus do not create any threads.
>
> I agree on what you are saying if I were to focus on a Provider, which
> will plug into server, serving to the multiple client requests.
>
> I still think we need to have switch to enable/disable multi threading.
>
> On 7 April 2012 23:40, Kirk Augustin <*[email protected]*<[email protected]>>
> wrote:
> It is unsafe for a single thread to call a multi-thread, but perfectly
> safe for a multi-thread to call a single thread.
> Multi-threading is the only safe way a service like Pegasus can call
> providers.
> If not multi threaded, then one faulty provider can corrupt all providers,
> as well as Pegasus, with an infinite deadlock.
> On HP UX you can mix multi thread and single thread.
> You just have to careful about singe thread library calling multi threaded
> libraries.
> Multi-threaded libraries have to call single threaded libraries all the
> time.
> A single thread library should always be passed data by value instead of
> reference, so should never need any synchronization protection.
> That can not possibly be a problem on any system.
>
> You are using the multi threading piece of code in Pegasus.
> It can not be unused.
> Pegasus is a remote network, communications systems, server, relying on
> sockets and an unknown number of provider plug-ins.
> It would be virtually inconceivable to imagine a good way that could be
> done without multi-threading.
> You could greatly increase the number of independent processes instead,
> and created more sockets or pipes to try to share data, but multi-threading
> is a much better solution to a multi tasking server like this.
> Your providers are best compiled as out of process, so have nothing to do
> with threading at all.
> Threading is only important within Pegasus.
> The question of threading really is not relevant because Pegasus is in
> control of what it calls, so will do so safely.
> All you have to worry about is your providers.
>
> Kirk Augustin
> 11821 NW McNamee Rd
> Portland, OR 97231
>
> HM: 503-289-4356
> ------------------------------
> *From:* Pranav S <*[email protected]* <[email protected]>>
> *To:* Kirk Augustin <*[email protected]* <[email protected]>>
> *
> Cc:* Devchandra Leishangthem <*[email protected]* <[email protected]>>;
> "*[email protected]* <[email protected]>" <*
> [email protected]* <[email protected]>> *
> Sent:* Saturday, April 7, 2012 10:37 AM
> *
> Subject:* Re: How to build OpenPegasus SDK as single threaded?
>
> On HP UX we cannot mix single threaded libraries with, multi-threaded
> ones. It might cause undefined behaviour.
> And, if an application links to multi-threaded library directly or
> indirectly, it has to be built with multi-threading (-mt option) enabled.
> As I am not using multi threaded piece of code from pegcommon(src/Common),
> I am expecting it to be disabled. Why unnecessarily create a dependency on
> pthread library? I believe it is good to have a flag in configure files
>  for enabling/disabling the multi-threading.
>
>
> On 6 April 2012 22:00, Kirk Augustin <*[email protected]*<[email protected]>>
> wrote:
> But if you turned off multi threading in Pegasus, you would create and
> ensure the very condition you are concerned about avoiding.
> You would cause a single threaded library to be linked with multi threaded
> ones.
> The only safe solution is to make sure Pegasus is multi treaded, so that
> you avoid the possibility of a single threaded library being linked to a
> multi threaded one.
> There is no risk in a multi threaded library linking to a single threaded
> one because a single threaded library gets multiple copies.
> Only the other way around is risky.
> There is only one copy of a multi threaded library, and you do not want
> single threaded libraries linking because then more than one could end up
> linking at the same time.
>
> Kirk  Augustin
> 11821 NW McNamee Rd
> Portland, OR 97231
>
> HM: 503-289-4356
> ------------------------------
> *From:* Pranav S <*[email protected]* <[email protected]>>*
> To:* Devchandra Leishangthem <*[email protected]* <[email protected]>>
> *
> Cc:* *[email protected]* <[email protected]> *
> Sent:* Friday, April 6, 2012 4:38 AM*
> Subject:* Re: How to build OpenPegasus SDK as single threaded?
>
> I some where read, on HPUX and AIX linking single threaded libraries to
> multi threaded causes undefined behaviour. Hence I was trying to to build
> openpegasus libs as single threaded. I see libpegcommon uses pthread
> library. I would like to know if there is way to turnoff the
> multithreading. In HPUX Makefiles I see "-mt" option being used to enable
> threads support.
>
> I see Pegasus/Common has thread pool implementation, which is not always
> being used by the applications consuming OenPegasus SDK.
> Let me know if I am wrong somewhere.
>
> Thank You,
> Pranav
>
> On 6 April 2012 16:22, Devchandra Leishangthem <*[email protected]*<[email protected]>>
> wrote:
> Is there any specifi reason why you wanted to build uni-threaded?
> Warm Regards
> D>L> Meetei
> IBM India System and Technology Lab
> EGL -D,Bangalore, India
>
>
>
> From:   Pranav S <*[email protected]* <[email protected]>>
> To:     *[email protected]* <[email protected]>,
> Date:   04/06/2012 04:06 PM
> Subject:        How to build OpenPegasus SDK as single threaded?
>
>
>
> Hello,
>
> I am trying to explore OpenPegasus SDK and its applications. Currently the
> SDK uses multi threading and links to pthreads library, hence it gets built
> as a multithreaded. I would like to know is it possible to build the
> library as single threaded? Do we have provision for that in the Makefiles.
> I tried exploring but did not find anything which tells that it is possible
> to build the library as single threaded one. Because linking a single
> threaded library to a multithreaded library can lead to undefined
> behaviour.
>
> --
> Thanks,
> Pranav
>
>
>
>
>
> --
> Thanks,
> Pranav
>
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>
>
> --
> Thanks,
> Pranav
>
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>
>
> --
> Thanks,
> Pranav
>
>
>
>
> --
> Thanks,
> Pranav
>
>
>
>
> --
> Thanks,
> Pranav
>
>
>
>
> --
> Thanks,
> Pranav
>
>


-- 
Thanks,
Pranav