Dr. Joel, So we can't say something solely on the basis of this result? On 2 Jun 2015 16:28, "Rohini Kulkarni" <krohini1...@gmail.com> wrote:
> I have not run it under linux on pi2 yet. Will have to run and check the > result. > On 2 Jun 2015 16:16, "Joel Sherrill" <joel.sherr...@oarcorp.com> wrote: > >> >> >> On June 2, 2015 5:58:33 AM EDT, Rohini Kulkarni <krohini1...@gmail.com> >> wrote: >> >HI, >> > >> >I tried running the dhrystone benchmark with some changes for cache/mmu >> >set up. >> > >> >However, the output shows a reduction in performance. >> >The time to run through the dhrystone has increased from 12 to 13 and >> >dhrystones run per second decreased. >> > >> >According to this result, things were better with caches disabled. >> > >> > >> >I have been working on this since two days and could not figure out an >> >improvement. Any pointers? >> >> How did it do under Linux on the Pi2? >> >> >> >Thanks. >> > >> > >> > >> >On Thu, May 28, 2015 at 8:41 PM, Rohini Kulkarni >> ><krohini1...@gmail.com> wrote: >> > >> >Hi All, >> > >> >I have to implement the cache coherency support for Cortex A7. But for >> >A7 MPCore, unlike for A9, I am not able to find any register >> >description for the Snoop Control Unit from the TRM. >> > >> >I need help here on how to proceed. >> > >> >Additionally for A9 there is a single bit for A9 in the Auxiliary >> >Control Register which enables cache broadcast operations. The register >> >format is different for A7 and again I am unable to find how to achieve >> >the same for A7. >> > >> >Thanks! >> > >> > >> > >> > >> > >> >On Tue, May 5, 2015 at 10:42 PM, Joel Sherrill >> ><joel.sherr...@oarcorp.com> wrote: >> > >> > >> > >> >On 5/5/2015 11:11 AM, Rohini Kulkarni wrote: >> > >> >Hi, >> > >> >I am working with the code for bsp hooks. I am referring to existing >> >ARM multicore bsp codes, zync mainly. >> > >> >1. There are existing hooks for the raspberry pi. Where should the code >> >for the Pi2 hooks be added? >> > >> >The Pi and Pi2 are remarkably similar so Pi2 should be placed inside >> >the Pi BSP directory. >> >There is already a Pi2 variant of that code built. But we know specific >> >places where there >> >are variances. Depending on the scope of what is different, it can be >> >as simple as >> >a cpp conditional in a .h to select a value or two implementations of a >> >single method >> >and the Makefile.am picking the right file to build based on the board >> >variant. >> > >> >The big question to always ask is: Is this specific to the Pi2 and >> >incompatible with the Pi? >> > >> >Since the Pi BSP is still missing capabilities, it is likely code >> >common to both will >> >be added this summer. For example, did the mailbox interface change? I >> >don't know >> >but would guess that it didn't. Each new capability added needs that >> >added. >> > >> >And any differences need to be analyzed to pick the least intrusive way >> >to provide >> >alternate implementations. Or enable special code like the Pi2 SMP >> >support which >> >is dependent on --enable-smp and being a Pi2. >> > >> >2. Am I right in understanding that I will have to implement A7 >> >specific functions as have been for A9? I am referring specifically to >> >the arm-a9mpcore-start.h >> > >> >Yes. >> > >> >If the code is very similar between the a7 and a9, then a discussion >> >on devel@ should occur to decide the best way to minimize duplication. >> > >> >If you end up with a7 specific code, you should follow the location and >> > >> >naming patterns already established. That places it in >> >libbsp/arm/shared/... >> >so it can be used by any BSP with the right SMP core. >> > >> > >> >I am referring to existing codes to locate and get hold of what needs >> >to be done in the hooks. However, being new to such implementations, I >> >am taking longer to understand the details. Any suggestions that might >> >help here are welcome >> > >> >The answer will depend on the factors listed above. When code can >> >be shared, we want to share it across as many BSPs as makes sense. >> >When it is unique to a specific BSP **variant** (e.g. Pi vs Pi2), then >> >you want to find the way to account for the variation in the least >> >intrusive code way possible. >> > >> >Thanks! >> > >> >On 1 May 2015 12:45, "Rohini Kulkarni" <krohini1...@gmail.com> wrote: >> > >> > >> >Hi, >> > >> >Excited to be a part of this edition of GSoC! Thanks to everybody for >> >helping me get here and congratulations to all the participating >> >students! >> > >> >So, now getting to work, firstly I wish to know, specifically from my >> >mentors, any changes that must be made to my proposed project or >> >schedule. >> > >> >Secondly, are there any specifics for the development blog that we need >> >to create for the project? Over time what is the blog expected to >> >convey. >> > >> >Also, I have to create a new wiki page for my project as none exists. I >> >want to know how to add one. >> > >> >-- >> > >> >Rohini Kulkarni >> > >> > >> >-- Joel Sherrill, Ph.D. Director of Research & Development >> >joel.sherr...@oarcorp.com On-Line Applications Research Ask me about >> >RTEMS: a free RTOS Huntsville AL 35805 Support Available (256) 722-9985 >> > >> > >> > >> > >> > >> >-- >> > >> >Rohini Kulkarni >> > >> > >> > >> > >> >-- >> > >> >Rohini Kulkarni >> >> --joel >> >
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