Fixes test failure
(https://github.com/valkey-io/valkey/actions/runs/10146979329/job/28056316421?pr=837)
on 32 bit system for slot stats metric underflow on the following
condition:
```
server.cluster->slot_stats[c->slot].network_bytes_out += (len * listLength(server.replicas));
```
* Here listLength accesses `len` which is of `unsigned long` type and
multiplied with `len` (which could be negative). This is a risky
operation and behaves differently based on the architecture.
```
clusterSlotStatsAddNetworkBytesOutForReplication(-sdslen(selectcmd->ptr));
```
* `sdslen` method returns `size_t`. applying `-` operation to decrement
network bytes out is also incorrect.
This change adds assertion on `len` being negative and handles the
wrapping of overall value.
---------
Signed-off-by: Harkrishn Patro <harkrisp@amazon.com>
Adds two new metrics for per-slot statistics, network-bytes-in and
network-bytes-out. The network bytes are inclusive of replication bytes
but exclude other types of network traffic such as clusterbus traffic.
#### network-bytes-in
The metric tracks network ingress bytes under per-slot context, by
reverse calculation of `c->argv_len_sum` and `c->argc`, stored under a
newly introduced field `c->net_input_bytes_curr_cmd`.
#### network-bytes-out
The metric tracks network egress bytes under per-slot context, by
hooking onto COB buffer mutations.
#### sample response
Both metrics are reported under the `CLUSTER SLOT-STATS` command.
```
127.0.0.1:6379> cluster slot-stats slotsrange 0 0
1) 1) (integer) 0
2) 1) "key-count"
2) (integer) 0
3) "cpu-usec"
4) (integer) 0
5) "network-bytes-in"
6) (integer) 0
7) "network-bytes-out"
8) (integer) 0
```
---------
Signed-off-by: Kyle Kim <kimkyle@amazon.com>
Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
The metric tracks cpu time in micro-seconds, sharing the same value as
`INFO COMMANDSTATS`, aggregated under per-slot context.
---------
Signed-off-by: Kyle Kim <kimkyle@amazon.com>
Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
