Hi Jerin, On Mon, Nov 04, 2019 at 12:59:40PM +0000, Jerin Jacob Kollanukkaran wrote: > Hi Anatoly and All, > > Just wondering what would the side effect of lowering a _bit_ of static > uint64_t baseaddr = 0x100000000 in > lib/librte_eal/common/eal_common_memory.c for 64bit systems. > > Use case: > If we _reserve_ VA address which less than 2^32 ONLY for packet > buffers(mbuf), The use cases like > Pipeline, where need to transfer packets from one core to another cores can > use ring element > size of 4B(32bit) which will reduce the a lot of read and write to enable > better > performance. > > i.e Since upper 32bits will be zero, it is matter of typecasting of item to > read and write from/to ring. > Essentially memcpy overhead for moving pointers over the ring will be half. > > Is baseaddr set to 2^32 to make sure that secondary process will have more > _chance_ of getting > the baseaddr in order for DPDK to work? > > Thoughts on above? On general to reduce the mbuf pointer storage requirement > for ring?
There are use cases where the mbufs take more than 4GB of memory, typically for protocols that do a lot of buffering/queing. So if anything is done in that direction, it has to be an option.
