Man page - ibv_read_counters(3)

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Manual

ibv_read_counters(3) Libibverbs Programmer’s Manual ibv_read_counters(3)

ibv_read_counters - Read counter values

#include <infiniband/verbs.h>
int ibv_read_counters(struct ibv_counters *counters,


                      uint64_t *counters_value,


                      uint32_t ncounters,


                      uint32_t flags);

ibv_read_counters() returns the values of the chosen counters into counters_value array of which can accumulate ncounters. The values are filled according to the configuration defined by the user in the ibv_attach_counters_point_xxx functions.

Counters object to read.
Input buffer to hold read result.
Number of counters to fill.
Use enum ibv_read_counters_flags.

flags Argument

Will prefer reading the values from driver cache, else it will do volatile hardware access which is the default.

ibv_read_counters() returns 0 on success, or the value of errno on failure (which indicates the failure reason)

Example: Statically attach counters to a new flow

This example demonstrates the use of counters which are attached statically with the creation of a new flow. The counters are read from hardware periodically, and finally all resources are released.

/* create counters object and define its counters points        */
/* create simple L2 flow with hardcoded MAC, and a count action */
/* read counters periodically, every 1sec, until loop ends      */
/* assumes user prepared a RAW_PACKET QP as input               */
/* only limited error checking in run time for code simplicity  */
#include <inttypes.h>
#include <infiniband/verbs.h>
/* the below MAC should be replaced by user */
#define FLOW_SPEC_ETH_MAC_VAL {


    .dst_mac = { 0x00, 0x01, 0x02, 0x03, 0x04,0x05},


    .src_mac = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},


    .ether_type = 0, .vlan_tag = 0, }
#define FLOW_SPEC_ETH_MAC_MASK {


    .dst_mac = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF},


    .src_mac = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF},


    .ether_type = 0, .vlan_tag = 0, }
void example_create_flow_with_counters_on_raw_qp(struct ibv_qp *qp) {


    int idx = 0;


    int loop = 10;


    struct ibv_flow *flow = NULL;


    struct ibv_counters *counters = NULL;


    struct ibv_counters_init_attr init_attr = {0};


    struct ibv_counter_attach_attr attach_attr = {0};


    /* create single counters handle */


    counters = ibv_create_counters(qp->context, &init_attr);


    /* define counters points */


    attach_attr.counter_desc = IBV_COUNTER_PACKETS;


    attach_attr.index = idx++;


    ret = ibv_attach_counters_point_flow(counters, &attach_attr, NULL);


    if (ret == ENOTSUP) {


        fprintf(stderr, "Attaching IBV_COUNTER_PACKETS to flow is not \
supported");


        exit(1);


    }


    attach_attr.counter_desc = IBV_COUNTER_BYTES;


    attach_attr.index = idx++;


    ibv_attach_counters_point_flow(counters, &attach_attr, NULL);


    if (ret == ENOTSUP) {


        fprintf(stderr, "Attaching IBV_COUNTER_BYTES to flow is not \
supported");


        exit(1);


    }


    /* define a new flow attr that includes the counters handle */


    struct raw_eth_flow_attr {


        struct ibv_flow_attr              attr;


        struct ibv_flow_spec_eth          spec_eth;


        struct ibv_flow_spec_counter_action spec_count;


    } flow_attr = {


        .attr = {


                .comp_mask  = 0,


                .type       = IBV_FLOW_ATTR_NORMAL,


                .size       = sizeof(flow_attr),


                .priority   = 0,


                .num_of_specs = 2, /* ETH + COUNT */


                .port       = 1,


                .flags      = 0,


            },


        .spec_eth = {


                .type = IBV_EXP_FLOW_SPEC_ETH,


                .size = sizeof(struct ibv_flow_spec_eth),


                .val  = FLOW_SPEC_ETH_MAC_VAL,


                .mask = FLOW_SPEC_ETH_MAC_MASK,


            },


        .spec_count = {


                .type   = IBV_FLOW_SPEC_ACTION_COUNT,


                .size   = sizeof(struct ibv_flow_spec_counter_action),


                .counters = counters, /* attached this counters handle
to the newly created ibv_flow */ } };


    /* create the flow */


    flow = ibv_create_flow(qp, &flow_attr.attr);


    /* allocate array for counters value reading */


    uint64_t *counters_value = malloc(sizeof(uint64_t) * idx);


    /* periodical read and print of flow counters */


    while (--loop) {


        sleep(1);


        /* read hardware counters values */


        ibv_read_counters(counters, counters_value, idx,


                  IBV_READ_COUNTERS_ATTR_PREFER_CACHED);


        printf("PACKETS = %"PRIu64", BYTES = %"PRIu64 \n",


            counters_value[0], counters_value[1] );


    }


    /* all done, release all */


    free(counters_value);


    /* destroy flow and detach counters */


    ibv_destroy_flow(flow);


    /* destroy counters handle */


    ibv_destroy_counters(counters);


    return;
}

ibv_create_counters, ibv_destroy_counters, ibv_attach_counters_point_flow, ibv_create_flow

Raed Salem raeds@mellanox.com

Alex Rosenbaum alexr@mellanox.com

2018-04-02 libibverbs