From 70dad9d6425d190771bf7a057bd6f8072f286d83 Mon Sep 17 00:00:00 2001
From: George Hotz <72895+geohot@users.noreply.github.com>
Date: Thu, 19 Mar 2026 18:57:40 +0800
Subject: [PATCH] add PING to RemoteCmd (#15371)

* add PING to RemoteCmd

* cleanup
---
 extra/remote/bench.py              | 12 +++++++-----
 extra/remote/serve.py              |  3 +++
 tinygrad/runtime/support/system.py |  2 +-
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/extra/remote/bench.py b/extra/remote/bench.py
index 8ab2052280..e747ba9d9f 100644
--- a/extra/remote/bench.py
+++ b/extra/remote/bench.py
@@ -16,12 +16,14 @@ if __name__ == "__main__":
   pci = RemotePCIDevice("BN", devs[0])
   print(f"connected to {os.environ['REMOTE']}, device: {devs[0]}\n")
 
-  # latency
-  for _ in range(10): pci.read_config(0, 4)
+  # ping (minimal server round-trip, no device I/O)
+  from tinygrad.runtime.support.system import RemoteCmd
+  sock = pci.sock
+  for _ in range(10): RemotePCIDevice._rpc(sock, 0, RemoteCmd.PING)
   st = time.perf_counter()
-  for _ in range(LAT_N_RUNS): pci.read_config(0, 4)
-  lat = (time.perf_counter() - st) / LAT_N_RUNS
-  print(f"RPC latency: {lat*1e6:.1f} us ({1/lat:,.0f} ops/sec)\n")
+  for _ in range(LAT_N_RUNS): RemotePCIDevice._rpc(sock, 0, RemoteCmd.PING)
+  ping_lat = (time.perf_counter() - st) / LAT_N_RUNS
+  print(f"PING latency: {ping_lat*1e6:.1f} us ({1/ping_lat:,.0f} ops/sec)\n")
 
   # throughput
   sysmem, _ = pci.alloc_sysmem(max(SIZES))
diff --git a/extra/remote/serve.py b/extra/remote/serve.py
index 736f3ba994..aa1af984a0 100644
--- a/extra/remote/serve.py
+++ b/extra/remote/serve.py
@@ -12,6 +12,9 @@ mapped_bars: dict[tuple[int, int], object] = {}
 sysmem_allocs: list[tuple] = []
 
 def handle(conn, cmd, dev_id, bar, arg0, arg1, arg2):
+  if cmd == RemoteCmd.PING:
+    return conn.sendall(resp())
+
   if cmd == RemoteCmd.PROBE:
     payload = conn.recv(arg1, socket.MSG_WAITALL) if arg1 > 0 else b""
     filter_devices: dict[int, list[int]] = {}
diff --git a/tinygrad/runtime/support/system.py b/tinygrad/runtime/support/system.py
index 7394bfc3ea..9352695e20 100644
--- a/tinygrad/runtime/support/system.py
+++ b/tinygrad/runtime/support/system.py
@@ -284,7 +284,7 @@ class PCIIfaceBase:
 # *** Remote PCI Devices
 
 class RemoteCmd(enum.IntEnum):
-  PROBE, MAP_BAR, MAP_SYSMEM_FD, CFG_READ, CFG_WRITE, RESET, MMIO_READ, MMIO_WRITE, MAP_SYSMEM, SYSMEM_READ, SYSMEM_WRITE, RESIZE_BAR = range(12)
+  PROBE,MAP_BAR,MAP_SYSMEM_FD,CFG_READ,CFG_WRITE,RESET,MMIO_READ,MMIO_WRITE,MAP_SYSMEM,SYSMEM_READ,SYSMEM_WRITE,RESIZE_BAR,PING = range(13)
 
 class RemoteMMIOInterface(MMIOInterface):
   def __init__(self, dev:RemotePCIDevice, residx:int, nbytes:int, fmt='B', off=0, rd_cmd=RemoteCmd.MMIO_READ, wr_cmd=RemoteCmd.MMIO_WRITE):