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Message-ID: <20251104232348.1954349-6-kuba@kernel.org>
Date: Tue, 4 Nov 2025 15:23:48 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: davem@...emloft.net,
donald.hunter@...il.com
Cc: netdev@...r.kernel.org,
edumazet@...gle.com,
pabeni@...hat.com,
andrew+netdev@...n.ch,
horms@...nel.org,
sdf@...ichev.me,
joe@...a.to,
jstancek@...hat.com,
Jakub Kicinski <kuba@...nel.org>
Subject: [PATCH net-next 5/5] tools: ynltool: add traffic distribution balance
The main if not only use case for per-queue stats today is checking
for traffic imbalance. Add simple traffic balance analysis to qstats.
$ ynltool qstat balance
eth0 rx 44 queues:
rx-packets : cv=6.9% ns=24.2% stddev=512006493
min=6278921110 max=8011570575 mean=7437054644
rx-bytes : cv=6.9% ns=24.1% stddev=759670503060
min=9326315769440 max=11884393670786 mean=11035439201354
...
$ ynltool -j qstat balance | jq
[
{
"ifname": "eth0",
"ifindex": 2,
"queue-type": "rx",
"rx-packets": {
"queue-count": 44,
"min": 6278301665,
"max": 8010780185,
"mean": 7.43635E+9,
"stddev": 5.12012E+8,
"coefficient-of-variation": 6.88525,
"normalized-spread": 24.249
},
...
Signed-off-by: Jakub Kicinski <kuba@...nel.org>
---
tools/net/ynl/ynltool/Makefile | 2 +-
tools/net/ynl/ynltool/qstats.c | 293 ++++++++++++++++++++++++++++++++-
2 files changed, 293 insertions(+), 2 deletions(-)
diff --git a/tools/net/ynl/ynltool/Makefile b/tools/net/ynl/ynltool/Makefile
index 1e860c63df66..2fe520f54ebb 100644
--- a/tools/net/ynl/ynltool/Makefile
+++ b/tools/net/ynl/ynltool/Makefile
@@ -24,7 +24,7 @@ all: $(YNLTOOL)
$(YNLTOOL): $(OBJS) $(LIBS)
@echo -e "\tLINK $@"
- @$(CC) $(CFLAGS) -o $@ $(OBJS) $(LIBS) -lmnl
+ @$(CC) $(CFLAGS) -o $@ $(OBJS) $(LIBS) -lmnl -lm
%.o: %.c main.h json_writer.h
@echo -e "\tCC $@"
diff --git a/tools/net/ynl/ynltool/qstats.c b/tools/net/ynl/ynltool/qstats.c
index fcdbb6d9a852..31fb45709ffa 100644
--- a/tools/net/ynl/ynltool/qstats.c
+++ b/tools/net/ynl/ynltool/qstats.c
@@ -5,6 +5,7 @@
#include <string.h>
#include <errno.h>
#include <net/if.h>
+#include <math.h>
#include <ynl.h>
#include "netdev-user.h"
@@ -13,6 +14,16 @@
static enum netdev_qstats_scope scope; /* default - device */
+struct queue_balance {
+ unsigned int ifindex;
+ enum netdev_queue_type type;
+ unsigned int queue_count;
+ __u64 *rx_packets;
+ __u64 *rx_bytes;
+ __u64 *tx_packets;
+ __u64 *tx_bytes;
+};
+
static void print_json_qstats(struct netdev_qstats_get_list *qstats)
{
jsonw_start_array(json_wtr);
@@ -293,6 +304,283 @@ static int do_show(int argc, char **argv)
return ret;
}
+static void compute_stats(__u64 *values, unsigned int count,
+ double *mean, double *stddev, __u64 *min, __u64 *max)
+{
+ double sum = 0.0, variance = 0.0;
+ unsigned int i;
+
+ *min = ~0ULL;
+ *max = 0;
+
+ if (count == 0) {
+ *mean = 0;
+ *stddev = 0;
+ *min = 0;
+ return;
+ }
+
+ for (i = 0; i < count; i++) {
+ sum += values[i];
+ if (values[i] < *min)
+ *min = values[i];
+ if (values[i] > *max)
+ *max = values[i];
+ }
+
+ *mean = sum / count;
+
+ if (count > 1) {
+ for (i = 0; i < count; i++) {
+ double diff = values[i] - *mean;
+
+ variance += diff * diff;
+ }
+ *stddev = sqrt(variance / (count - 1));
+ } else {
+ *stddev = 0;
+ }
+}
+
+static void print_balance_stats(const char *name, enum netdev_queue_type type,
+ __u64 *values, unsigned int count)
+{
+ double mean, stddev, cv, ns;
+ __u64 min, max;
+
+ if ((name[0] == 'r' && type != NETDEV_QUEUE_TYPE_RX) ||
+ (name[0] == 't' && type != NETDEV_QUEUE_TYPE_TX))
+ return;
+
+ compute_stats(values, count, &mean, &stddev, &min, &max);
+
+ cv = mean > 0 ? (stddev / mean) * 100.0 : 0.0;
+ ns = min + max > 0 ? (double)2 * (max - min) / (max + min) * 100 : 0.0;
+
+ printf(" %-12s: cv=%.1f%% ns=%.1f%% stddev=%.0f\n",
+ name, cv, ns, stddev);
+ printf(" %-12s min=%llu max=%llu mean=%.0f\n",
+ "", min, max, mean);
+}
+
+static void
+print_balance_stats_json(const char *name, enum netdev_queue_type type,
+ __u64 *values, unsigned int count)
+{
+ double mean, stddev, cv, ns;
+ __u64 min, max;
+
+ if ((name[0] == 'r' && type != NETDEV_QUEUE_TYPE_RX) ||
+ (name[0] == 't' && type != NETDEV_QUEUE_TYPE_TX))
+ return;
+
+ compute_stats(values, count, &mean, &stddev, &min, &max);
+
+ cv = mean > 0 ? (stddev / mean) * 100.0 : 0.0;
+ ns = min + max > 0 ? (double)2 * (max - min) / (max + min) * 100 : 0.0;
+
+ jsonw_name(json_wtr, name);
+ jsonw_start_object(json_wtr);
+ jsonw_uint_field(json_wtr, "queue-count", count);
+ jsonw_uint_field(json_wtr, "min", min);
+ jsonw_uint_field(json_wtr, "max", max);
+ jsonw_float_field(json_wtr, "mean", mean);
+ jsonw_float_field(json_wtr, "stddev", stddev);
+ jsonw_float_field(json_wtr, "coefficient-of-variation", cv);
+ jsonw_float_field(json_wtr, "normalized-spread", ns);
+ jsonw_end_object(json_wtr);
+}
+
+static int cmp_ifindex_type(const void *a, const void *b)
+{
+ const struct netdev_qstats_get_rsp *qa = a;
+ const struct netdev_qstats_get_rsp *qb = b;
+
+ if (qa->ifindex != qb->ifindex)
+ return qa->ifindex - qb->ifindex;
+ if (qa->queue_type != qb->queue_type)
+ return qa->queue_type - qb->queue_type;
+ return qa->queue_id - qb->queue_id;
+}
+
+static int do_balance(int argc, char **argv __attribute__((unused)))
+{
+ struct netdev_qstats_get_list *qstats;
+ struct netdev_qstats_get_req *req;
+ struct netdev_qstats_get_rsp **sorted;
+ struct ynl_error yerr;
+ struct ynl_sock *ys;
+ unsigned int count = 0;
+ unsigned int i, j;
+ int ret = 0;
+
+ if (argc > 0) {
+ p_err("balance command takes no arguments");
+ return -1;
+ }
+
+ ys = ynl_sock_create(&ynl_netdev_family, &yerr);
+ if (!ys) {
+ p_err("YNL: %s", yerr.msg);
+ return -1;
+ }
+
+ req = netdev_qstats_get_req_alloc();
+ if (!req) {
+ p_err("failed to allocate qstats request");
+ ret = -1;
+ goto exit_close;
+ }
+
+ /* Always use queue scope for balance analysis */
+ netdev_qstats_get_req_set_scope(req, NETDEV_QSTATS_SCOPE_QUEUE);
+
+ qstats = netdev_qstats_get_dump(ys, req);
+ netdev_qstats_get_req_free(req);
+ if (!qstats) {
+ p_err("failed to get queue stats: %s", ys->err.msg);
+ ret = -1;
+ goto exit_close;
+ }
+
+ /* Count and sort queues */
+ ynl_dump_foreach(qstats, qs)
+ count++;
+
+ if (count == 0) {
+ if (json_output)
+ jsonw_start_array(json_wtr);
+ else
+ printf("No queue statistics available\n");
+ goto exit_free_qstats;
+ }
+
+ sorted = calloc(count, sizeof(*sorted));
+ if (!sorted) {
+ p_err("failed to allocate sorted array");
+ ret = -1;
+ goto exit_free_qstats;
+ }
+
+ i = 0;
+ ynl_dump_foreach(qstats, qs)
+ sorted[i++] = qs;
+
+ qsort(sorted, count, sizeof(*sorted), cmp_ifindex_type);
+
+ if (json_output)
+ jsonw_start_array(json_wtr);
+
+ /* Process each device/queue-type combination */
+ i = 0;
+ while (i < count) {
+ __u64 *rx_packets, *rx_bytes, *tx_packets, *tx_bytes;
+ enum netdev_queue_type type = sorted[i]->queue_type;
+ unsigned int ifindex = sorted[i]->ifindex;
+ unsigned int queue_count = 0;
+ char ifname[IF_NAMESIZE];
+ const char *name;
+
+ /* Count queues for this device/type */
+ for (j = i; j < count && sorted[j]->ifindex == ifindex &&
+ sorted[j]->queue_type == type; j++)
+ queue_count++;
+
+ /* Skip if no packets/bytes (inactive queues) */
+ if (!sorted[i]->_present.rx_packets &&
+ !sorted[i]->_present.rx_bytes &&
+ !sorted[i]->_present.tx_packets &&
+ !sorted[i]->_present.tx_bytes)
+ goto next_ifc;
+
+ /* Allocate arrays for statistics */
+ rx_packets = calloc(queue_count, sizeof(*rx_packets));
+ rx_bytes = calloc(queue_count, sizeof(*rx_bytes));
+ tx_packets = calloc(queue_count, sizeof(*tx_packets));
+ tx_bytes = calloc(queue_count, sizeof(*tx_bytes));
+
+ if (!rx_packets || !rx_bytes || !tx_packets || !tx_bytes) {
+ p_err("failed to allocate statistics arrays");
+ free(rx_packets);
+ free(rx_bytes);
+ free(tx_packets);
+ free(tx_bytes);
+ ret = -1;
+ goto exit_free_sorted;
+ }
+
+ /* Collect statistics */
+ for (j = 0; j < queue_count; j++) {
+ rx_packets[j] = sorted[i + j]->_present.rx_packets ?
+ sorted[i + j]->rx_packets : 0;
+ rx_bytes[j] = sorted[i + j]->_present.rx_bytes ?
+ sorted[i + j]->rx_bytes : 0;
+ tx_packets[j] = sorted[i + j]->_present.tx_packets ?
+ sorted[i + j]->tx_packets : 0;
+ tx_bytes[j] = sorted[i + j]->_present.tx_bytes ?
+ sorted[i + j]->tx_bytes : 0;
+ }
+
+ name = if_indextoname(ifindex, ifname);
+
+ if (json_output) {
+ jsonw_start_object(json_wtr);
+ if (name)
+ jsonw_string_field(json_wtr, "ifname", name);
+ jsonw_uint_field(json_wtr, "ifindex", ifindex);
+ jsonw_string_field(json_wtr, "queue-type",
+ netdev_queue_type_str(type));
+
+ print_balance_stats_json("rx-packets", type,
+ rx_packets, queue_count);
+ print_balance_stats_json("rx-bytes", type,
+ rx_bytes, queue_count);
+ print_balance_stats_json("tx-packets", type,
+ tx_packets, queue_count);
+ print_balance_stats_json("tx-bytes", type,
+ tx_bytes, queue_count);
+
+ jsonw_end_object(json_wtr);
+ } else {
+ if (name)
+ printf("%s", name);
+ else
+ printf("ifindex:%u", ifindex);
+ printf(" %s %d queues:\n",
+ netdev_queue_type_str(type), queue_count);
+
+ print_balance_stats("rx-packets", type,
+ rx_packets, queue_count);
+ print_balance_stats("rx-bytes", type,
+ rx_bytes, queue_count);
+ print_balance_stats("tx-packets", type,
+ tx_packets, queue_count);
+ print_balance_stats("tx-bytes", type,
+ tx_bytes, queue_count);
+ printf("\n");
+ }
+
+ free(rx_packets);
+ free(rx_bytes);
+ free(tx_packets);
+ free(tx_bytes);
+
+next_ifc:
+ i += queue_count;
+ }
+
+ if (json_output)
+ jsonw_end_array(json_wtr);
+
+exit_free_sorted:
+ free(sorted);
+exit_free_qstats:
+ netdev_qstats_get_list_free(qstats);
+exit_close:
+ ynl_sock_destroy(ys);
+ return ret;
+}
+
static int do_help(int argc __attribute__((unused)),
char **argv __attribute__((unused)))
{
@@ -304,6 +592,7 @@ static int do_help(int argc __attribute__((unused)),
fprintf(stderr,
"Usage: %s qstats { COMMAND | help }\n"
" %s qstats [ show ] [ OPTIONS ]\n"
+ " %s qstats balance\n"
"\n"
" OPTIONS := { scope queue | group-by { device | queue } }\n"
"\n"
@@ -312,14 +601,16 @@ static int do_help(int argc __attribute__((unused)),
" show scope queue - Display per-queue statistics\n"
" show group-by device - Display device-aggregated statistics (default)\n"
" show group-by queue - Display per-queue statistics\n"
+ " balance - Analyze traffic distribution balance.\n"
"",
- bin_name, bin_name);
+ bin_name, bin_name, bin_name);
return 0;
}
static const struct cmd qstats_cmds[] = {
{ "show", do_show },
+ { "balance", do_balance },
{ "help", do_help },
{ 0 }
};
--
2.51.1
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