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Question about BPF map type BPF_MAP_TYPE_PERCPU_HASH

Raga lahari
 

Hi everyone,


I am using BPF_MAP_TYPE_HASH in BPF map definition and my program is working  as expected. 

I have read eBPF-map type  BPF_MAP_TYPE_PERCPU_HASH allows for lock free uses of hash-tables in eBPF for high performance needs. 

I am trying to modify BPF map type from BPF_MAP_TYPE_HASH to BPF_MAP_TYPE_PERCPU_HASH. But, when I run the program,  I am getting issues in  BPF map iteration (using bpf_map_get_next_key)


Can someone help me to know any points need to consider to use BPF_MAP_TYPE_PERCPU_HASH map type . 



Thanks,

Ragalahari

Yonghong Song
 

On Thu, Jan 31, 2019 at 12:09 AM Raga lahari <ragalahari.potti@...> wrote:

Hi everyone,


I am using BPF_MAP_TYPE_HASH in BPF map definition and my program is working as expected.

I have read eBPF-map type BPF_MAP_TYPE_PERCPU_HASH allows for lock free uses of hash-tables in eBPF for high performance needs.

I am trying to modify BPF map type from BPF_MAP_TYPE_HASH to BPF_MAP_TYPE_PERCPU_HASH. But, when I run the program, I am getting issues in BPF map iteration (using bpf_map_get_next_key)


Can someone help me to know any points need to consider to use BPF_MAP_TYPE_PERCPU_HASH map type .
You can take a look at bcc/tests/cc/{test_array_table.cc,
test_hash_table.cc, test_bpf_table.cc}.
There are a few examples there testing percpu maps.




Thanks,

Ragalahari