Commit 82c45080 authored by Kumar Kartikeya Dwivedi's avatar Kumar Kartikeya Dwivedi Committed by Alexei Starovoitov
Browse files

samples: bpf: Add xdp_exception tracepoint statistics support 



This implements the retrieval and printing, as well the help output.

Signed-off-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-8-memxor@gmail.com
parent 45158876

samples/bpf/xdp_sample_user.c

+113 −0
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ 
enum map_type {

	MAP_RX,

	MAP_REDIRECT_ERR,

	MAP_EXCEPTION,

	NUM_MAP,

};
@@ -98,6 +99,7 @@ struct map_entry { 
struct stats_record {

	struct record rx_cnt;

	struct record redir_err[XDP_REDIRECT_ERR_MAX];

	struct record exception[XDP_ACTION_MAX];

};



struct sample_output {
@@ -115,6 +117,9 @@ struct sample_output { 
		__u64 suc;

		__u64 err;

	} redir_cnt;

	struct {

		__u64 hits;

	} except_cnt;

};



struct xdp_desc {
@@ -156,6 +161,15 @@ static const char *xdp_redirect_err_help[XDP_REDIRECT_ERR_MAX - 1] = { 
	"No space in ptr_ring of cpumap kthread",

};



static const char *xdp_action_names[XDP_ACTION_MAX] = {

	[XDP_ABORTED]  = "XDP_ABORTED",

	[XDP_DROP]     = "XDP_DROP",

	[XDP_PASS]     = "XDP_PASS",

	[XDP_TX]       = "XDP_TX",

	[XDP_REDIRECT] = "XDP_REDIRECT",

	[XDP_UNKNOWN]  = "XDP_UNKNOWN",

};



static __u64 gettime(void)

{

	struct timespec t;
@@ -169,6 +183,13 @@ static __u64 gettime(void) 
	return (__u64)t.tv_sec * NANOSEC_PER_SEC + t.tv_nsec;

}



static const char *action2str(int action)

{

	if (action < XDP_ACTION_MAX)

		return xdp_action_names[action];

	return NULL;

}



static void sample_print_help(int mask)

{

	printf("Output format description\n\n"
@@ -206,6 +227,15 @@ static void sample_print_help(int mask) 


		printf("  \n\t\t\t\terror/s   - Packets that failed redirection per second\n\n");

	}



	if (mask & SAMPLE_EXCEPTION_CNT) {

		printf("  xdp_exception\t\tDisplays xdp_exception tracepoint events\n"

		       "  \t\t\tThis can occur due to internal driver errors, unrecognized\n"

		       "  \t\t\tXDP actions and due to explicit user trigger by use of XDP_ABORTED\n"

		       "  \t\t\tEach action is expanded below this field with its count\n"

		       "  \t\t\t\thit/s     - Number of times the tracepoint was hit per second\n\n");

	}



}



void sample_usage(char *argv[], const struct option *long_options,
@@ -327,9 +357,26 @@ static struct stats_record *alloc_stats_record(void) 
			}

		}

	}

	if (sample_mask & SAMPLE_EXCEPTION_CNT) {

		for (i = 0; i < XDP_ACTION_MAX; i++) {

			rec->exception[i].cpu = alloc_record_per_cpu();

			if (!rec->exception[i].cpu) {

				fprintf(stderr,

					"Failed to allocate exception per-CPU array for "

					"\"%s\" case\n",

					action2str(i));

				while (i--)

					free(rec->exception[i].cpu);

				goto end_redir;

			}

		}

	}



	return rec;



end_redir:

	for (i = 0; i < XDP_REDIRECT_ERR_MAX; i++)

		free(rec->redir_err[i].cpu);

end_rx_cnt:

	free(rec->rx_cnt.cpu);

end_rec:
@@ -343,6 +390,8 @@ static void free_stats_record(struct stats_record *r) 
	struct map_entry *e;

	int i;



	for (i = 0; i < XDP_ACTION_MAX; i++)

		free(r->exception[i].cpu);

	for (i = 0; i < XDP_REDIRECT_ERR_MAX; i++)

		free(r->redir_err[i].cpu);

	free(r->rx_cnt.cpu);
@@ -551,6 +600,50 @@ static void stats_get_redirect_err_cnt(struct stats_record *stats_rec, 
	}

}



static void stats_get_exception_cnt(struct stats_record *stats_rec,

				    struct stats_record *stats_prev,

				    unsigned int nr_cpus,

				    struct sample_output *out)

{

	double t, drop, sum = 0;

	struct record *rec, *prev;

	int rec_i, i;



	for (rec_i = 0; rec_i < XDP_ACTION_MAX; rec_i++) {

		rec = &stats_rec->exception[rec_i];

		prev = &stats_prev->exception[rec_i];

		t = calc_period(rec, prev);



		drop = calc_drop_pps(&rec->total, &prev->total, t);

		/* Fold out errors after heading */

		sum += drop;



		if (drop > 0 && !out) {

			print_always("    %-18s " FMT_COLUMNf "\n",

				     action2str(rec_i), ERR(drop));



			for (i = 0; i < nr_cpus; i++) {

				struct datarec *r = &rec->cpu[i];

				struct datarec *p = &prev->cpu[i];

				char str[64];

				double drop;



				drop = calc_drop_pps(r, p, t);

				if (!drop)

					continue;



				snprintf(str, sizeof(str), "cpu:%d", i);

				print_default("       %-16s" FMT_COLUMNf "\n",

					      str, ERR(drop));

			}

		}

	}



	if (out) {

		out->except_cnt.hits = sum;

		out->totals.err += sum;

	}

}



static void stats_print(const char *prefix, int mask, struct stats_record *r,

			struct stats_record *p, struct sample_output *out)
@@ -595,6 +688,16 @@ static void stats_print(const char *prefix, int mask, struct stats_record *r, 
		stats_get_redirect_err_cnt(r, p, nr_cpus, NULL);

	}



	if (mask & SAMPLE_EXCEPTION_CNT) {

		str = out->except_cnt.hits ? "xdp_exception total" :

						   "xdp_exception";



		print_err(out->except_cnt.hits, "  %-20s " FMT_COLUMNl "\n", str,

			  HITS(out->except_cnt.hits));



		stats_get_exception_cnt(r, p, nr_cpus, NULL);

	}



	if (sample_log_level & LL_DEFAULT ||

	    ((sample_log_level & LL_SIMPLE) && sample_err_exp)) {

		sample_err_exp = false;
@@ -617,6 +720,9 @@ int sample_setup_maps(struct bpf_map **maps) 
			sample_map_count[i] =

				XDP_REDIRECT_ERR_MAX * sample_n_cpus;

			break;

		case MAP_EXCEPTION:

			sample_map_count[i] = XDP_ACTION_MAX * sample_n_cpus;

			break;

		default:

			return -EINVAL;

		}
@@ -788,6 +894,11 @@ static int sample_stats_collect(struct stats_record *rec) 
					   &rec->redir_err[i]);

	}



	if (sample_mask & SAMPLE_EXCEPTION_CNT)

		for (i = 0; i < XDP_ACTION_MAX; i++)

			map_collect_percpu(&sample_mmap[MAP_EXCEPTION][i * sample_n_cpus],

					   &rec->exception[i]);



	return 0;

}
@@ -811,6 +922,8 @@ static void sample_stats_print(int mask, struct stats_record *cur, 
		stats_get_redirect_cnt(cur, prev, 0, &out);

	if (mask & SAMPLE_REDIRECT_ERR_CNT)

		stats_get_redirect_err_cnt(cur, prev, 0, &out);

	if (mask & SAMPLE_EXCEPTION_CNT)

		stats_get_exception_cnt(cur, prev, 0, &out);

	sample_summary_update(&out, interval);



	stats_print(prog_name, mask, cur, prev, &out);

samples/bpf/xdp_sample_user.h

+3 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ enum stats_mask { 
	_SAMPLE_REDIRECT_MAP        = 1U << 0,

	SAMPLE_RX_CNT               = 1U << 1,

	SAMPLE_REDIRECT_ERR_CNT     = 1U << 2,

	SAMPLE_EXCEPTION_CNT        = 1U << 5,

	SAMPLE_REDIRECT_CNT         = 1U << 7,

	SAMPLE_REDIRECT_MAP_CNT     = SAMPLE_REDIRECT_CNT | _SAMPLE_REDIRECT_MAP,

	SAMPLE_REDIRECT_ERR_MAP_CNT = SAMPLE_REDIRECT_ERR_CNT | _SAMPLE_REDIRECT_MAP,
@@ -75,6 +76,8 @@ static inline char *safe_strncpy(char *dst, const char *src, size_t size) 
			__attach_tp(tp_xdp_redirect_map_err);                  \

		if (mask & SAMPLE_REDIRECT_ERR_CNT)                            \

			__attach_tp(tp_xdp_redirect_err);                      \

		if (mask & SAMPLE_EXCEPTION_CNT)                               \

			__attach_tp(tp_xdp_exception);                         \

		return 0;                                                      \

	}