[ydl-gen] Linux yellow dog manual for dummies

Rob Sanders rarob at travelinglightfarm.net
Sun Dec 27 05:28:27 JST 2009 

Warren,
   I'd concur.  This application was hugely floating point  
intensive.  Graphics ops were not an issue for us.  The app used only  
low-level X11 calls (no Motif, or Xt calls even), so what graphics  
there were under OSX had to go through Apple's X11 layer before being  
seen.  Most of the testing I had done was using the XServe as the  
compute host, with graphics being redirected to a remote terminal.   
But I still consistently saw about a 2x speed improvement when the  
app ran on YLD 4 vice OSX 10.3.  <sigh>  Many fond memories....

-Rob

On Dec 26, 2009, at 3:00 PM, Warren Nagourney wrote:

> I think one needs to distinguish between the OS and the CPU. My  
> experience with the G5 is that its floating point performance is  
> between 1.5x and 2x as fast as the equivalent x86. Unfortunately,  
> the fixed point advantages are not there. I use LaTeX a lot and  
> heard that the typesetting speed improved on Macs (running OS X)  
> when Apple switched to intel (same TeX source - this might me in  
> part a reflection on the poorer PPC optimizations in gcc).  The  
> intel advantage might be 20% in LaTeX typesetting (this is a single  
> data point from a commercial TeX).
>
> On the other hand, the performance of the OS is another matter.  
> Every linux I have installed on a Mac (or PS3) was much less  
> responsive than OS X for similar operations. This is a combination  
> of things like application launching speed and particularly  
> graphics operations, which are slow in PPC linux since there are no  
> good PPC drivers for video cards in linux.  This is entirely a user  
> interface issue and a PPC linux server might do very well compared  
> to the competition (I have no experience with this). Of course, the  
> speed of apps which don't use graphics should be the same between  
> linux and OS X since they both use the same compilers.
>
> Cheers,
>
> Warren Nagourney
>
> On Dec 26, 2009, at 8:09 AM, Rob Sanders wrote:
>
>> I haven't done much with YDL in some time as I've changed jobs,  
>> but I'd just like to chime in that several years ago that the PPC  
>> Linux's ( YDL for Mac, full RedHat/SuSE on some IBM OpenPower720  
>> hardware) was running rings around the equivalent x86 -or- Alpha  
>> based platforms we were doing some work on.  Tried to get my  
>> bosses & customers more interested in it and hit the wall of 'but  
>> it isn't x86'.  <sigh>.  At the time, a direct comparison of the  
>> *same* base code on a Mac XServe G5 running on YDL4 vice OS X 10.3  
>> had the YDL code twice as fast as the OS X code.  Lots of double  
>> precision floating point math, and multiple processes (not  
>> threads) communicating via shared memory.  We would routinely max  
>> out any box we were running on.
>>
>> -Rob
>>
>> On Dec 25, 2009, at 2:37 PM, Warren Nagourney wrote:
>>
>>> Thanks, Derick.
>>>
>>> Although this is a YDL forum, I am afraid to say that there is no  
>>> comparison between any linux on PPC and OS X. The former simply  
>>> doesn't have the software base that I need. I used to think that  
>>> it would be faster than OS X, but after a few installations of  
>>> linux on Apple computers, I discovered that OS X wins hands down  
>>> in the speed area as well. I think that linux is optimized for  
>>> x86 and of course things like flash are only available on x86  
>>> linux (I hate flash, but it unfortunately has become a standard  
>>> for internet video). There are still some PPC optimizations in OS  
>>> X apps and maybe even some Altivec usage (which allows Quicktime  
>>> to smoothly run at 1080p on my PPC machines). The tasks involved  
>>> in writing my book would have been enormously greater if I had  
>>> used linux instead of OS X.
>>>
>>> I notice an increasing dominance of ARM in low power portable  
>>> devices. This is unfortunate, since ARM simply doesn't have the  
>>> computational power that PPC has - I am not sure it even has a  
>>> floating point data type. It is too bad that IBM did such a poor  
>>> job of promoting PPC; we will need to reinvent the wheel with ARM  
>>> when we could have had advanced multi-purpose chips with low  
>>> power consumption from the PPC manufacturers (such as PA semi,  
>>> which Apple bought and converted to ARM).
>>>
>>> Anyway, the improvement in the performance of Apple products  
>>> since the switch has been less than stellar, much less than  
>>> expected from Moore's law. My 4 year old G5 has a 1.15 GHz memory  
>>> bus and an 16x dual layer superdrive, which is very competitive  
>>> with the best that Apple can come up with now (for reasonable  
>>> prices). It cost much less than a current machine and doesn't  
>>> require a several thousand dollar investment in software, which I  
>>> would need to make if I use one of Apple's intel superboxes.
>>>
>>> Cheers,
>>>
>>> Warren Nagourney
>>>
>>> On Dec 24, 2009, at 2:28 PM, Derick Centeno wrote:
>>>
>>>> You may want to know that you may find decent parts for your system
>>>> from http://macsales.com/
>>>>
>>>> I think we may have to really keep our PowerPC running for  
>>>> longer than
>>>> that although I did hear of someone developing a multicore PowerPC
>>>> laptop a month or so ago.  I've got to search for who this  
>>>> fellow is
>>>> again as I lost track, but I did hear of a fellow who created a  
>>>> working
>>>> Cell based laptop which ran the GameOS and had the OtherOS option.
>>>> Pretty neat!
>>>>
>>>> Caveat:  If you replace the power supply or other support parts you
>>>> shouldn't have trouble running YDL from it.  Be careful  
>>>> regarding other
>>>> components however such as DVD drives: if those go it may be  
>>>> wiser to
>>>> consider an external DVD drive in that situation.  I'm unsure if  
>>>> anyone
>>>> we knew remains at Fixstars from TSS; it may not be so easy to  
>>>> get the
>>>> kind of support we became accustomed to.  In any case, I'd  
>>>> advise you
>>>> to consider reviewing what notations remain regarding their  
>>>> advisories
>>>> regarding which hardware works with YDL and which do not.  As  
>>>> best I
>>>> recall, the past emphasis (by TSS) was to support original Apple  
>>>> parts.
>>>>
>>>> So the problems to watch for may not be RAM as much as internal
>>>> associated devices, such as a newer hard drive or modem or  
>>>> something
>>>> similar.  It may be better to just get an HD which resides on a PCI
>>>> card which your system should recognize with no problem as an  
>>>> external
>>>> system; I don't think such a drive would be able to be booted from
>>>> within YDL.  It would be interesting to try that out as a concept
>>>> though.
>>>>
>>>> Anyway enjoy and all the best!!
>>>>
>>>> On Thu, 24 Dec 2009 13:57:49 -0800
>>>> Warren Nagourney <warren at phys.washington.edu> wrote:
>>>>
>>>>> Thanks, Derick. I  still love the PPC architecture and recently
>>>>> bought an Apple dual core 2.3 GHz G5 for very little money and am
>>>>> finding it to be absolutely as fast as I could ever hope for. I  
>>>>> will
>>>>> keep it for the next 3-5 years (assuming I can keep the power  
>>>>> supply
>>>>> running) and maybe then, the dominance of x86 may have lessened  
>>>>> (it
>>>>> can't last forever!).
>>>>>
>>>>> Merry Christmas and Happy 2010,
>>>>>
>>>>> Warren N
>>>>
>>>>
>>>>
>>>>
>>>> =========
>>>>
>>>> Refranes/Popular sayings:
>>>> The Taino say:No hay mal que por bien no venga.
>>>> There is no evil out of which good cannot blossom.
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