On 04-Nov-19 12:59 PM, 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?
You can already try that with --base-virtaddr option if you have such
specific addressing requirements. That said, the address is pretty much
arbitrary, so i'm not against lowering it in principle, it just feels
like a workaround for something that's very specific to the workloads
you are targetting.
--
Thanks,
Anatoly
