# tt_fabric_tx_heartbeat_total

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## Name

### Prometheus Metric Name

```
tt_fabric_tx_heartbeat_total
```

### Metric Path (tt-telemetry)

Schema:

```
{hostname}/tray{tray}/chip{chip}/channel{channel}/fabric/erisc{erisc_core}/tt_fabric_tx_heartbeat_total
```

Example path:

```
bh-glx-c09u02/tray1/chip2/channel0/fabric/erisc0/tt_fabric_tx_heartbeat_total
```

## Description

The transmit heartbeat counter for a specific eRISC core on a fabric Ethernet channel. This counter increments as the eRISC core processes transmit operations. If it stops incrementing, the eRISC TX path may be hung. This metric is available on Wormhole B0 and Blackhole devices.

Note: Fabric metrics are only updated by fabric firmware when workloads are run with fabric telemetry explicitly enabled. For example, by setting the environment variable `TT_METAL_FABRIC_TELEMETRY` to `1`.

## Values

**Type:** Unsigned Integer

**Units:** None

**Allowable values:**
A non-negative integer that increments over time. The absolute value is not meaningful; what matters is that it continues to change between successive reads.

## Prometheus Labels

|Label Name|Value|
|---|---|
|hostname|The host from which the metric was collected.|
|hall|The datacenter hall where the host is located. Sourced from the Factory System Descriptor (FSD).|
|aisle|The datacenter aisle where the host is located. Sourced from the Factory System Descriptor (FSD).|
|rack|The rack number where the host is located. Sourced from the Factory System Descriptor (FSD).|
|shelf_u|The shelf U position in the rack where the host is located. Sourced from the Factory System Descriptor (FSD).|
|tray|The tray (UBB) that the device is located on.|
|chip|The ASIC location within the tray.|
|channel|The Ethernet channel number on the chip.|
|port_type|The physical port type (e.g., QSFP, backplane). Present when topology information is available.|
|port_id|The physical port ID. Present when topology information is available.|
|remote_hostname|The hostname of the remote endpoint. Present when remote endpoint information is available.|
|remote_tray|The tray number of the remote endpoint. Present when remote endpoint information is available.|
|remote_chip|The ASIC location of the remote endpoint. Present when remote endpoint information is available.|
|remote_channel|The Ethernet channel of the remote endpoint. Present when remote endpoint information is available.|
|remote_hall|The datacenter hall of the remote endpoint. Present when remote endpoint information is available.|
|remote_aisle|The datacenter aisle of the remote endpoint. Present when remote endpoint information is available.|
|remote_rack|The rack number of the remote endpoint. Present when remote endpoint information is available.|
|remote_shelf_u|The shelf U position of the remote endpoint. Present when remote endpoint information is available.|
|erisc_core|The eRISC core index (0 for Wormhole, 0-1 for Blackhole).|