Cell BE: theoretical-maximum performance.

[Coded-Dude]

Unlike on conventional processors, you can achieve near theoretical-maximum performance for real applications on the Cell Broadband Engine™ (Cell BE) processor. For this, you must be aware of the Cell BE processor's architectural characteristics: get to know them better with these 25 tips to optimal application performance.

TIPS IN DETAIL (http://www-128.ibm.com/developerworks/power/library/pa-celltips1/?ca=dgr-lnxw09OptimalAppPerformance)

Cell BE system practices
Tip 1: Offload as much work onto the SPEs as possible
Tip 2: Choose a partitioning and work allocation strategy that minimizes atomic operations and synchronization events
Tip 3: Accommodate potential data type differences

PPE programming practices
Tip 4: Exploit multithreading
Tip 5: Self-manage cache
Tip 6: Avoid microcoded opcodes

Memory subsystem programming practices
Tip 7: Make efficient use of programmer-managed data transfers
Tip 8: Design data structures for efficient access
Tip 9: Initiate DMAs from the SPE
Tip 10: Lock to avoid thrashing
Tip 11: Allocate large data sets from large pages to reduce page table and TLB thrashing
Tip 12: Maintain synchronization variables in their own reservation block
Tip 13: Uniformly distribute memory bank accesses
Tip 14: Stay on-chip

SPE programming practices
Tip 15: Avoid external scalars
Tip 16: Exploit SIMD
Tip 17: Understand the instruction set and issue rules
Tip 18: Choose optimal SIMD strategy
Tip 19: Unroll and pipeline loops
Tip 20: Overlap data movement with computation
Tip 21: Eliminate or reduce branches
Tip 22: Avoid integer multiplies
Tip 23: Use offset pointers
Tip 24: Consider computing versus using pre-computed results
Tip 25: Design for limited local store

The Cell BE processor is a very powerful processing complex. Specialized programming techniques employed either directly by the programmer or indirectly through tools (like compilers) can pay great dividends toward application performance. Armed with the strategies and techniques outlined in this article, you can realize the full potential of the Cell Broadband Engine processor.

There are some very interesting alternatives to standard practices, that some of you might finf pretty interesting. I put this in tech central becasue it is not directly realted to PS3, rather it focuses more on programing for CELL in general.

cheers!

[PhYmon]

This processor is very cool, I mean u can do a bunch of tasks on one clock than any other convencional CPUs, the idea of having SPE's on CELL is not that original but also a risky one.. But if IBM use it for a server's purpose (and beat BlueGene/L's record) I can feel a good vibe going with this new processor and the evolution that I can achive over the time.

[Garfunkel]

I am starting to get more confident of CELL's abilities as time goes on, it seems that the "emotion engine 2" might live up to its promise, it is capable of some pretty amazing things and is pretty cleverly made too

nice work dude, +rep

[PhYmon]

Im getting to think that Cell is more like the Brain.. the more u studied the more complex it gets.. and if u learn how it works, u can discover the mysteries of this life! :P Im j/k but seriously Cell is a great piece of technology.

[Garfunkel]

user: "CELL, what is the answar to life, the unerverse and everything?"

CELL: (after a great pause of many years) "42"

user: (gasps) "...what is the question?"

CELL: "............."

-to be continued

[PhYmon]

Why "42"?? it could easily be 46 or 43? I hope it goes good Yes_It's_Me

[Garfunkel]

if you didn't get it, you haven't read the hitchhikers guide to the galaxy by Douglas Adams.

[PhYmon]

I didnt :(

[cpiasminc]

Tip 2: Choose a partitioning and work allocation strategy that minimizes atomic operations and synchronization events
Hmm... I love how they make that sound so simple. It's only a problem that is provably unsolvable in a general case... so it's only natural to sound easy when you give the canonical case.

Tip 4: Exploit multithreading [on PPE]
I find it interesting that they don't give away an even bigger reason why multithreading on the PPE is an absolute necessity to getting out the theoretical power.

Tip 15: Avoid external scalars
Tip 16: Exploit SIMD
Tip 17: Understand the instruction set and issue rules
Tip 18: Choose optimal SIMD strategy
Tip 19: Unroll and pipeline loops
In other words, get used to counting cycles.

[PhYmon]

They are to blame u know I mean with the whole minimizes "atomic operation and sync events" cuz they make u believe that everything is easy and smooth with Cell which isnt, and the we get mad at the developers cuz they dont use the full potencial of the hardware,but I know that develop for Cell is pretty hard cuz is a new architecture and all that stuff, but my guess is, that once u get to know the processor and how all works it would be easier to for.

[Garfunkel]

well i guess all the middleware they brang in helps alot too.

[PhYmon]

The middleware only shows a few tricks or how things can get done on Cell, but the middleware arent everything, developers, they make their own way into the system but first they use the middleware tools to know the behavior and all the technical stuff the have to know..

[cpiasminc]

The biggest value with most middleware is the tools it provides and the art pipeline. It's often much cheaper to spool up an in house physics engine than it is to buy Havok or NovodeX... But making good tools so that the content creators can create good, effective collision geometry that actually doesn't horribly disagree with the system, and also effectively debug problems when they come up -- that's horrid and extremely time consuming.

With any option, you still have to pound on the core computational code and rip it apart to suit each individual title and its content, but at least with a middleware option you don't have to worry all the time about making artists happy [they have someone else to bug], which is something programmers like.

All the nifty tricks you can pull with a particular architecture are not widely solved by anyone yet... and that includes middleware developers. They have all the same problems every other game development studio has.

[overclocked]

The biggest value with most middleware is the tools it provides and the art pipeline. It's often much cheaper to spool up an in house physics engine than it is to buy Havok or NovodeX... But making good tools so that the content creators can create good, effective collision geometry that actually doesn't horribly disagree with the system, and also effectively debug problems when they come up -- that's horrid and extremely time consuming.

With any option, you still have to pound on the core computational code and rip it apart to suit each individual title and its content, but at least with a middleware option you don't have to worry all the time about making artists happy [they have someone else to bug], which is something programmers like.

All the nifty tricks you can pull with a particular architecture are not widely solved by anyone yet... and that includes middleware developers. They have all the same problems every other game development studio has.

Speaking of that how was/is the latest versions of PS2 middlewhere-tools just for reference?

The developers that has Cell must be able to figure out this things on their own imo, its good for hobby-coders though.

Credit for general support and theres alot for Cell coming it seems but for anyone even including me,
i think atleast half of those tip´s i could have answered right on if it was a test because of things i have read and learned about the architecture.

[venomv]

I didnt :(

You should at least see the movie.