Thanks Ramesh. I was reserving and mapping buffers "every time". This was not required. I modified the code to reserve and map a buffer only once and use the mapped address for future. This modification reduced the overhead. I have one more doubt. Does DSP use virtual-to-physical mapping for all the addresses it accesses (including DSP's local buffers)? Or it uses this mapping only to access shared buffers? Wont it be a big overhead if DSP accesses all the memories through virtual-to-physical mapping? Regards, Viraj -----Original Message----- From: Ramesh Gupta G [mailto:x0023949@xxxxxx] Sent: Monday, June 09, 2008 11:03 AM To: Viraj Karandikar; linux-omap-open-source@xxxxxxxxxxxxxx Subject: Re: Sharing buffers between ARM-DSP on OMAP3430 over Bridge Hi Vijay, ----- Original Message ----- From: "Viraj Karandikar" <viraj.karandikar@xxxxxxxxxx> To: <linux-omap-open-source@xxxxxxxxxxxxxx> Sent: Saturday, June 07, 2008 3:45 PM Subject: Sharing buffers between ARM-DSP on OMAP3430 over Bridge >Hi all, >I am working on omap3430 using bridge. I am using Dynamically Mapped >Memory (DMM) method for sharing buffers. >For sending buffers to DSP I am doing calls to >DSPProcessor_ReserveMemory() and DSPProcessor_Map(). For these calls are >taking around 18ms (for 3-4MB buffers) which is not acceptable for the >application. I am not able to understand why it is taking so much time? Which version of bridge you are using? We have optimized the code for DSPProcessor_Map(), You can see significant change in the numbers with the latest code. >My understanding of DMM method is -> >- Use malloc() to allocate a buffer on ARM. >- Reserve required chunk of memory from DMM pool (using >DSPProcessor_ReserveMemory() ) >- Translate this memory to ARM virtual address space in >DSPProcessor_Map() function. Actually DSPProcessor_Map() maps ARM physical addresses to DSP Virtual addresses. >- Send the reserved memory address to DSP. >Is this correct? I am confused about how exactly this happens. You are correct except above point about DSPProcessor_Map(). >Also Ihave a doubt if the reserved memory address is from DSP physical address >space? Or is it from ARM virtual address space for DSP physical address >space? Reserved Memory is from DSP Virtual Address. >Is DMM method does copy from malloc'ed address to reserved >address in any way? Do you mean copying the contents? No copying is involved. Only mapping of addresses is performed. >It will be helpful if anybody put some light on this. Please let me know if you see any issues. >Regards, >Viraj Thanks & Regards Ramesh Gupta G ********************************************************************** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify helpdesk@xxxxxxxxxxx ********************************************************************** _______________________________________________ Linux-omap-open-source mailing list Linux-omap-open-source@xxxxxxxxxxxxxx http://linux.omap.com/mailman/listinfo/linux-omap-open-source -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
