Optimizing software for your DSP application

admin mcoaep , , , , , , ,

first_imgShare this:TwitterFacebookLinkedInMoreRedditTumblrPinterestWhatsAppSkypePocketTelegram Tags: Design Methods Experienced embedded-systems programmers already know most of the tricks to optimize code to a target platform, but many of us have come relatively recently to embedded-systems programming, having learned our coding skills on less constrained platforms. There we didn’t have to worry too much about hardware details beyond general efficiency of algorithms, but in embedded applications we need to be a lot more careful, certainly for performance but also to fit what we would like to do to the practical limitations of our hardware target, especially in types and size of available memory. Memory in these systems is the suitcase into which you must fit all your software and all your working data, and the suitcase is often a lot smaller than you would prefer it to be.Source: CEVA As an added complication, there’s often more than one type of memory in these systems. To keep programming simple, you see just one logical memory space, but some address ranges may be implemented in hardware in different ways. Some of the space may be implemented as external main memory, accessible from the processor through one or more levels of cache.A common hardware optimization will implement another range as tightly-coupled memory (TCM). This sits inside the same chip as the processor, usually right next to that processor. TCM provides guaranteed single-clock-cycle access for any instructions or data stored in that memory, unlike standard memory which will only be able to provide that performance if the instruction/data is already in cache; otherwise it has to go out to the main memory, taking many more clock cycles. TCM is one example of (memory-mapped) fast on-chip memory; there can be other uses, such as for image buffers for fast access in image processing.One more consideration – using on-chip memory reduces power consumption, whereas going to main memory draws more power, thanks to higher current to drive all those package pins and board interconnects between chips. This is an important consideration in low-power applications.Why not just use big on-chip memories and load/store infrequently from off-chip? Unfortunately large on-chip memories increase chip area significantly, and as chip size grows the device becomes more expensive and less competitive. System architects have to be very careful to balance performance gains against this cost, considering whether they might only provide say 16KB of TCM versus as much as perhaps 1MB. That puts a lot of responsibility back on you, the programmer, to use or plan these memories (if you have a say in early chip architecture) as frugally and carefully as you possibly can, especially when it comes to which functions or data you want to use fast memory.Some of what you need to do here is fairly obvious; I’ll assume you’re starting either with a PC-based implementation or an implementation developed for an earlier product. Since you’re obviously interested in DSPs, you probably plan to do a lot of floating-point calculations. Reduce datatypes from double-precision to single-precision wherever you can; this alone might cut data-size in half.Scratch memory pools, a method to allocate chunks of memory in one go to serve the needs of multiple smaller related allocation needs, are popular for speed in allocation and deallocation but can be very expensive in memory. Try to merge all of these into one memory pool as long as they’re not used in parallel or bite the bullet and return to traditional mallocs on the heap; this may be a bit slower but can be a lot more efficient in memory.Especially when it comes to TCM, profile the code to find the functions which consume the most run-time. Your strategy here is going to be to decide which of these, starting with the highest-demand function, you can fit into the TCM. Of course there has to be some judgement here. If a high-demand function calls a low-demand function, can you afford to have that low-demand function pulled from cache? Maybe this will be OK as long as the cache-hit rate will be high or if an occasional longer delay is tolerable.An example where a longer delay might be OK would be in a music player supporting both MP3 and FLAC decoders. You’re only going to use one at most per song, so they don’t both need to be resident in fast memory. Accept the delay to load whichever is needed, on demand from off-chip into the fast memory.You want to squeeze production code and data to the smallest size possible, so as a point of general good hygiene, make sure that all debug, profiling and logging code is bracketed in pragmas which can be disabled for production build. In PC-code you might not worry too much about this (especially if you want to run the debugger on production software) but here it’s essential. Conversely, you also should make sure you run all your regression tests with that code disabled. It only takes one overlooked run-time dependency inside the debug to create downstream nightmares.Equally, make sure that every bit of code inside your software is being used. Run coverage tests. If you find code that isn’t being used, maybe it’s a hangover from an earlier rev where it might have been needed. Here it isn’t, so you should be able to get rid of it, right? Again, you have to be careful. Maybe it’s error-handling for a very rare case which can’t be overlooked. Maybe it should be included in the regression tests but it’s too hard to trigger directly. You’ll have to decide based on discussion with the architect and maybe the hardware team.And finally, argue with the architect (and marketing if needed) about which of the features they are demanding be included are really essential. They might not realize that after every optimization you can possibly think of, the suitcase still won’t close. Then they’re going to have to decide which really cool feature they really, really wanted may have to be sacrificed. Or maybe they have to go back to the business team and demand larger on-chip memories, using information you can provide on just how much those memories need to grow. Either way, you’re going to look good!Ariel Hershkovitz serves as CEVA’s Senior Manager of Customer Solutions for Software Development Tools. Ariel brings over 14 years of multi-disciplinary experience, spanning software development, verification, integration and deployment of software deliveries, in both technical and managerial roles. He is passionate about user experiences, ease of use and innovative technology. Highly proficient in analyzing complex problems and simplifying them for rapid resolution. Ariel holds a B.Sc. in Computer Science from Ben-Gurion University, and an MBA from Bar-Ilan University.. Continue Reading Previous Elatec: universal reader that’s smaller than a credit cardNext congatec: new SMARC module with NXP i.MX 8M Mini processorcenter_img Leave a Reply Cancel reply You must Register or Login to post a comment. This site uses Akismet to reduce spam. Learn how your comment data is processed.last_img

You May Also Like..

Facies and depositional processes in an Upper Jurassic to Lower Cretaceous pelagic sedimentary sequence, Antarctica

first_imgThe Nordenskjöld Formation (?Oxfordian-Berriasian age) is exposed on the east coast of the Antarctic Peninsula, where it consists of interbedded ash layers and biosiliceous mudstones which accumulated under anaerobic to dysaerobic bottom waters. The mudstones were deposited by pelagic settling and the ash layers by pelagic settling from suspension or as fallout from subaerial eruption columns. The lower part of the succession accumulated in a basinal setting under anaerobic bottom waters and is characterized by parallel bedding. Mudstones deposited in this setting preserve abundant zooplankton faecel pellets. Compaction of these pellets has given rise to a bedding parallel fissility. The upper part of the succession accumulated under dysaerobic bottom waters in a slope setting. The sequence is wavy bedded and contains abundant evidence of post-depositional sediment instability and resedimentation, much of which was caused by tectonic activity. Discrete slide masses are absent from the slope sequence and it appears that slope processes were dominated by creep. Examination of the mudstones shows that as levels of dissolved oxygen in bottom waters increase, pelleted mudstones give way to structureless mudstones before visible bioturbation is noted.last_img

Radiography Program Coordinator

first_imgEEO Statement FLSAExempt Preferred Education/Training/Experience Mid Point Salary RangeTBD Ability to develop Radiography courses and curricula andeffectively teach Radiography coursesProficient in curriculum design, evaluation, instruction, programadministration, and academic advisingWorking knowledge of the Joint Review Committee in RadiologicTechnology ( JRCERT ), American Registry of Radiologic Technologies( ARRT ) and Texas Higher Education Coordinating Boardstandards Job Duties Maximum Salary Range -Prepare, develop, revise curriculum and course work. Meet classesas scheduled. Complete paperwork/tests and issue student grades asscheduled. Maintain office hours for student consultation-Establish an advisory board-Responsible for development of all aspects of the program,including the organization, administration, continuous review,planning, development, and general effectiveness of theprogram-Responsible for organization, administration, continuous review,planning, development, and general effectiveness of clinicalexperiences for students enrolled in the Radiography program-Overseeing ongoing program accreditation and assessmentprocesses-Participating in budget planning-Participating in didactic and/or clinical instruction, asappropriate-Maintaining current knowledge of the professional discipline andeducation methodologies through continuing professionaldevelopment-Assuming the leadership role in the continued development of theprogram-This position will initially report to the Director of ProgramDevelopment and is responsible for performing tasks and assignmentsgiven by the Director. Other duties as appropriate to theposition Documents Needed to ApplyRequired DocumentsResumeCover LetterTranscripts (1 of 3)Optional Documents The Allied Health Department is seeking a full time temporaryRadiography program coordinator who will be responsible fordeveloping curricula and coursework for our new RadiographyAssociate Degree program and once active, possibly providinginstruction within the Radiography and allied programs asqualified. In addition, the coordinator will be responsible forproviding scheduled office hours for student consultation, serve onCollege committees as needed and assigned, and participating instudent orientated instructional and advisement activities asneeded and assigned. Employment StatusTemporary Physical Requirements Doctorate degree in Radiologic Science or related area. Threeyears’ teaching experience in Radiography courses at a community ortwo-year collegePrevious experience in Radiography program development Positions in this class typically require: reaching, standing,fingering, grasping, talking, hearing, and seeing. Sedentary Work:Exerting up to 10 pounds of force occasionally and/or a negligibleamount of force frequently or constantly to lift, carry, push, pullor otherwise move objects, including the human body. Sedentary workinvolves sitting most of the time. Jobs are sedentary if walkingand standing are required only occasionally and all other sedentarycriteria are met.The employee frequently is required to sit. The employee isoccasionally required to stand, walk; use hands to finger, handle,or feel objects, tools, or controls; reach with hands and arms;climb or balance; and stoop, kneel, crouch, or crawl. The employeemust occasionally lift and/or move up to 45 pounds.Specific vision abilities required by this job include closevision, distance vision, color vision, peripheral vision, depthperception, and the ability to adjust focus. Licensing/Certification Requirements Preferred Knowledge & Skills Multi-modality certification, i.e.: Computed Tomography (CT),Magnetic Resonance Imaging ( MRI ), Sonography (US), InterventionalRadiography (IR)Experience in the JRCERT accreditation or re-accreditationprocessKnowledge of online and/or hybrid teaching formatsExperience using simulation aids for laboratory experience Contract LengthN/A Position TitleRadiography Program Coordinator Position TypeFacultycenter_img Position Details Posting Open Date12/09/2020 Posting NumberF139P Supplemental QuestionsRequired fields are indicated with an asterisk (*). Candidates that are eligible applyInternal/External Posting Close Date Master’s degree with 18 hours in a specialized fieldDocumented three years’ clinical experience in the professionaldisciplineDocumented two years’ experience as an instructor in a JRCERT-accredited program Minimum Education/Training/Experience Class Summary Special Instructions to Applicant * Do you have at least a Master’s degree with 18 hours in aspecialized field, three years’ clinical experience in theprofessional discipline, and at least two years’ experience as aninstructor in a JRCERT-accredited program?YesNo Quick Link for Direct Access to Postinghttps://jobs.com.edu/postings/2359 Open Until Filled College of the Mainland is an affirmative action/equal opportunityinstitution and does not discriminate on the basis of race, color,sex, age, national origin, religion, disability or veteranstatus.College of the Mainland does not discriminate on the basis ofdisability in the recruitment and admission of students, therecruitment and employment of faculty and staff, and the operationof its programs and activities, as specified by federal laws andregulations within Section 504 of the Rehabilitation Act of 1973and the Americans with Disabilities Act of 1990 and 1992. Current American Registry of Radiologic Technologists ( ARRT )certification and registration, or equivalent, inradiography. Minimum Salary RangeTBD Minimum Knowledge & Skills Position FundingRegularlast_img

The Dangers of Fauxstalgia

first_imgUnsurprisingly, fauxstalgia is a financially lucrative business. Cashing in on the trend are bands as musically diverse as Take That and the Pixies, both of whom have performed to sold-out arenas on their recent comeback tours, with tickets exchanging hands for more than £200 on E-Bay. In the case of Take That, it was notable that the only former member of the band who did not participate in their reunion tour of 2006 was also the only one to have enjoyed a profitable music career since their demise almost a decade earlier. Likewise, by the time of the Pixies’ reunion in 2004, they had been defunct for twelve years and the royalties had dwindled substantially. Yet, as the BBC website reviewer said of the latter, “If nothing else comes out of this comeback tour other than a healthier bank balance for the four members of the Pixies then that’s fine, but that doesn’t have to mean that I won’t be down at the front of the stage in 2014 for their next show, manically singing along to Monkey Gone To Heaven, pretending I’m a teenager again.” It seems that you can’t put a price on fauxstalgia. The latest to be announced in this recent spate of fauxstalgia-friendly comeback tours is that of the Spice Girls. Despite reports that they will earn a not-to-be-sniffed-at sum of £10 million each for the tour, the sponsorship, the accompanying documentary, and the inevitable greatest hits album, Geri has staunchly denied that money is a motivating factor for their reunion. Instead she attributes the reason for the tour to “nostalgia”, which is interesting if we consider that it was she who brought about their demise, dramatically resigning her place in the band during their world tour in 1998, on the grounds of in-band “differences”. At the recent press launch she said, “we’re doing this because it’s a once-in-a-life-time opportunity to be a Spice Girl again. Who would turn that down?” Who indeed, particularly if your last attempt at a solo-album, Passion, was met with such a distinctly passionless response that it failed even to reach the top-forty on first release. “Obviously it’s nostalgic,” she continued, “but  equally, if new fans want to come along, that’s fantastic.” And fauxstalgia is certainly to be cited for the astounding fact that the £85 tickets to the London dates of the tour sold out in just 38 seconds. As LMH second-year, gleeful golden-ticket holder and fauxstalgic fan, Gerard Lee, said, “Geri had already left the band by the time I got the chance to see them at Wembley Arena in 1998 so I decided I’d have to go this time round and see them all together”. Is anyone ever too young to indulge in a little nostalgia now and then? Perhaps there are babies who pine for the halcyon days of the womb. “Oh, alas for the amniotic fluid, the vitamin-rich food on tap, the lovely cosiness” they would moan if only they knew how. Instead, they pass their time wordlessly wailing for what has been. Perhaps there are children, on their first day of nursery school, who heave a little sigh for the dearly departed – the onesies, the high-chair, the cot – before stoically resigning themselves to the serious, grown-up business of tidying the Wendy house and making sure that the Cabbage Patch doll gets to bed on time. Certainly, at the not-too-ancient age of twenty, I’m no stranger to a spot of ‘fauxstalgia’ – that is, nostalgia for those who are young enough to know better. Midnight essay crises tend to induce severe bouts of fauxstalgia, during which I pine for my spoon-fed, well-read school days when I was a mere snip of a thing at eighteen. Gender divides at parties, Billie Piper on Top of the Pops (RIP), Starbucks-free high streets, and fake IDs comprise some of the things for which I’m occasionally fauxstalgic. And I’m not the only one. Indulging in fauxstalgia is a national hobby, largely thanks to the wonders of digital cameras, which allow us to pore over a photo only a moment after it has been taken (“didn’t we look pretty five minutes ago?”). Yet, the term ‘fauxstalgia’ does not only apply to this kind of premature nostalgia for things only recently past. Fauxstalgia also encompasses our false nostalgia for those things past which we never actually experienced ourselves. That today’s fashions are so heavily influenced by the styles of bygone eras, from the mini-dresses of the sixties to the maxi-dresses of the seventies, most likely represents a dearth of creative inspiration but may perhaps also be symptomatic of our fauxstalgic tendencies. In fact, this reverence of yesteryear leads to the irony that anything awarded the suffix ‘retro’, whether it be music, fashion or film, is automatically up-to-the-minute. From my adamance that Baby Spice and I were soulsisters (“we have the same name and we both have blonde hair!”) to my long-overdue epiphany as to the meaning of ‘Two Become One’, the Spice Girls are bound up with many of my formative childhood memories. Not least do I remember the tremulous thrill of buying a packet of Spice Girls photographs (the latest ‘official’ merchandise product to guzzle my pocket-money), only to discover that fate had dealt me a cruel hand since this new acquisition did not contain that rare photo for which I longed but rather was a duplicate of a packet I already possessed. Yet, despite my predilection for Spice Girls fauxstalgia of this kind, I shall not be joining the ranks of former fans in begging, borrowing, stealing or selling my vital organs in the hope of obtaining a ticket. In fact, I’m thoroughly disillusioned by the hype surrounding the Spice Girls’ reunion and, contrary to appearances, this is not due to any lingering photo-related bitterness. In my opinion, seeing the Spice Girls on their comeback tour will never be able to mean to me now what it did originally, not so much because I myself have changed but rather because the five members of the band have changed. Though the intricacies of the feminist ideology possibly underlying the motto, ‘Girl Power’, were lost on me as a child, I nevertheless appreciated the spirit of female friendship and sisterhood which the Spice Girls represented to girls of my age. Yet, the photo shoot which accompanied the press launch for their comeback tour made it abundantly clear that no such camaraderie still exists between them. No longer resembling a cohesive five-piece, no longer even friends, they stood stiffly as five individuals, all of whom are unrecognisable from their former individual ‘Spice’ personas. Mel C, Mel B and Emma, once Sporty, Scary and Baby respectively, were indistinguishable from one another, demurely and blandly dressed in top-to-toe black. Geri, in stark incongruity, was serenely encased in swathes of white fabric, perhaps in a misguided attempt to dispel the image of her as the black sheep of the band. Yet, the sight of Victoria alone, her impossible breasts vying for attention and chihauhua-like frame squeezed into a corset, was enough to confirm that the endearing ordinariness and outspoken, girl-next-door charm which accounted for much of the Spice Girls’ appeal has long been lost. Indeed, she is no longer the likeable and fun Posh Spice of old but rather she is one half of so-called ‘Brand Beckham’, ironically managed in this enterprise by Simon Fuller, the media svengali whom the Spice Girls notoriously sacked as their manager during their heydey. Ruthlessly dedicated to her own self-promotion, from ‘DVB’ perfumes to her personal online blog, her entire image has been strategically crafted by a team of publicists with military precision. The Spice Girls’ comeback tour is a bloated, cynical and ultimately pointless operation, not unlike ‘Brand Beckham’ itself. It’s a half-hearted resurrection of what was successful in its day; a shadow of its former self. It can only disappoint those leagues of fauxstalgia-driven fans who have come to see the Spice Girls as they once knew and loved them. Save your £85 and see Girls Aloud instead. Fauxstalgia is so last year.  By Emma Bernsteinlast_img

Leave a Reply

Your email address will not be published. Required fields are marked *