[Error debug] PHV allocation was not successful

Getting Started with P4
1

Hello, does anyone know how to solve the error: PHV allocation was not successful. I am trying to convert bmv2 program to tofino. Part of the code and error prompts is attached below. Let me know if you need more info. I very appreciate your help.

struct my_ingress_metadata_t {
bit<2> meter_color;
bit<32> weight;
bit<32> threshold;
bit<32> plr;
bit<32> current_rate;
bit<32> demand;
bit<32> flow_h1;
bit<48> flow_time;
tPort_t destinationPort;
bit<16> next_rate_tbl;
bit<16> next_demand_tbl;
bit<10> meter_index;
bit<32> flow_byte_counter;
bit<32> prev_flow_byte_counter;
bit<32> flow_last_time_stamp_32;
bit<32> flow_last_time_stamp_16;
bit<32> delta;
bit<48> time_diff;
}

control Ingress(
    /* User */
    inout my_ingress_headers_t                       hdr,
    inout my_ingress_metadata_t                      meta,
    /* Intrinsic */
    in    ingress_intrinsic_metadata_t               ig_intr_md,
    in    ingress_intrinsic_metadata_from_parser_t   ig_prsr_md,
    inout ingress_intrinsic_metadata_for_deparser_t  ig_dprsr_md,
    inout ingress_intrinsic_metadata_for_tm_t        ig_tm_md)
{   

    Register<bit<32>, bit<REGISTER_CELL_WIDTH>>(REGISTER_SIZE_TOTAL, 0) flow_payload_counter;
    RegisterAction<bit<32>, bit<32>, bit<32>>(flow_payload_counter) write_flow_payload_counter = {
        void apply(inout bit<32> write_value){
            write_value = meta.flow_byte_counter;
        }
    };

    ...
    
    apply {
          /* write to register */
          meta.flow_byte_counter  = meta.flow_byte_counter + (bit<32>)hdr.ipv4.totalLen;
          write_flow_payload_counter.execute(meta.flow_h1);
    }
}

error prompts:

========================= make.log =========================
error: PHV allocation was not successful

3 field slices remain unallocated

The following fields were not allocated: 

    ingress::meta.flow_byte_counter<32b>[15:0]

    ingress::hdr.ipv4.totalLen<16b>

    ingress::meta.flow_byte_counter<32b>[31:16]

Number of P4 compiler-proper ERRORs: 2

Number of P4 compiler-proper WARNINGs: 11

Number of errors exceeded set maximum of 1

make[2]: *** [CMakeFiles/l4_learning_tna-tofino.dir/build.make:73: l4_learning_tna/tofino/bf-rt.json] Error 3

make[2]: *** Deleting file 'l4_learning_tna/tofino/bf-rt.json'

make[1]: *** [CMakeFiles/Makefile2:166: CMakeFiles/l4_learning_tna-tofino.dir/all] Error 2

make: *** [Makefile:136: all] Error 2

========================= make.log =========================
2

Dear @HangHu,

Welcome to the forum! I

You can find a lot of useful information on this forum, especially if you use its search function ( :mag:). For example, a simple search on the “tofino” keyword will immediately produce this post , which contains the necessary recommendations.

Also, if you you haven’t done it already, I’d highly recommend you attend Intel Connectivity Academy by P4ica courses.

Happy hacking,
Vladimir

3

Dear Vladimir,

Thank you very much for your suggestions. Also, my colleague has enrolled in the upcoming P4 course.

4

Hello Hang,

I am really glad you followed the advice and I hope it was helpful, was it not?

For the benefit of those who might find themselves in a similar situation, we can now report that you reached out via ICRP forum (as was suggested), where you promptly received a specific recommendation that solved the issue.

Happy hacking,
Vladimir