Check the EPC and free RAM sizes before running the experiments

By default, abort if either is too small, but you can set the env var
SHRINK_TO_MEM=1 to instead run smaller experiments that should fit in
the available resources.

run_all_experiments.py

@@ -1,6 +1,31 @@
 #!/usr/bin/python3
 
+import os
+import re
+import subprocess
+import sys
 from run_experiments import run_exp
+from epc_probe import get_max_epc_bytes
+
+def get_free_gib():
+    """Get the number of free GiB of memory"""
+    ret = subprocess.run(["free", "-m"], capture_output=True)
+    if ret.returncode != 0:
+        print("Unable to run free", file=sys.stderr)
+        sys.exit(1)
+    match = re.search(r'Mem:\s*\d+\s+\d+\s+(\d+)', str(ret.stdout))
+    if match is None:
+        print("Unable to parse output of free", file=sys.stderr)
+        sys.exit(1)
+    free_mem_mib = int(match.group(1))
+    return free_mem_mib / 1024
+
+# How much memory is available?
+free_gib = get_free_gib()
+
+# How much EPC is available?
+epc_gib = get_max_epc_bytes() / (1<<30)
+
 
 LOG_FOLDER = "Experiments/"
 
@@ -11,10 +36,54 @@ PUB_OUT = 1
 PUB_IN = 1
 # B = message size (bytes)
 B = 256
+N_MAX = 1<<20
+M_MAX = 72
+
+# Typical EPC sizes are slightly less than a power of 2.
+# For 1<<20 clients and 72 servers, we need 4.25 GiB of EPC and 20 GiB
+# of free RAM.
+# If we don't have that, abort, unless the SHRINK_TO_MEM env var is set
+# to 1, in which case perform smaller experiments that should fit in the
+# available resources.
+if epc_gib < 4.25 or free_gib < 20:
+    shrink_to_mem = \
+        os.getenv("SHRINK_TO_MEM", '0').lower() in ('true', '1', 't')
+    if not shrink_to_mem:
+        if epc_gib < 4.25:
+            print(f"""
+*** Available EPC appears to be {epc_gib:.2f} GiB; 4.25 GiB is
+*** needed to run the full set of experiments.
+""")
+        if free_gib < 20:
+            print(f"""
+*** Free RAM appears to be {free_gib:.2f} GiB; 20 GiB is
+*** needed to run the full set of experiments.
+""")
+        print("""
+*** Set the env var SHRINK_TO_MEM=1 to run a smaller set of
+*** experiments that should fit in the available resources.
+""")
+        sys.exit(1)
+    if epc_gib > 3.9 and free_gib > 14:
+        N_MAX = 1<<19
+        M_MAX = 72
+    elif epc_gib > 1.9 and free_gib > 7.5:
+        N_MAX = 1<<18
+        M_MAX = 64
+    elif epc_gib > 0.9 and free_gib > 4.2:
+        N_MAX = 1<<17
+        M_MAX = 48
+    else:
+        print(f"""
+*** You have too small EPC ({epc_gib:.2f} GiB) and/or free
+*** memory ({free_gib:.2f} GiB) to run TEEMS, even with
+*** SHRINK_TO_MEM set to 1
+""")
+        sys.exit(1)
 
 ## Figure 5 Public
 PRIVATE_ROUTE = False
-N = [1<<15, 1<<16, 1<<17, 1<<18, 1<<19, 1<<20]
+N = [n for n in [1<<15, 1<<16, 1<<17, 1<<18, 1<<19, 1<<20] if n <= N_MAX]
 M = [4]
 T = [4]
 
@@ -22,15 +91,15 @@ run_exp(LOG_FOLDER, PRIVATE_ROUTE, NUM_EPOCHS, N, M, T, B, PRIV_OUT, PRIV_IN, PU
 
 ## Figure 6 Public
 PRIVATE_ROUTE = False
-N = [1<<20]
-M = [72, 64, 48, 36, 32, 24, 16, 8, 6, 4]
+N = [N_MAX]
+M = [m for m in [72, 64, 48, 36, 32, 24, 16, 8, 6, 4] if m <= M_MAX]
 T = [1]
 
 run_exp(LOG_FOLDER, PRIVATE_ROUTE, NUM_EPOCHS, N, M, T, B, PRIV_OUT, PRIV_IN, PUB_OUT, PUB_IN)
 
 ## Figure 5 Private
 PRIVATE_ROUTE = True
-N = [1<<15, 1<<16, 1<<17, 1<<18, 1<<19, 1<<20]
+N = [n for n in [1<<15, 1<<16, 1<<17, 1<<18, 1<<19, 1<<20] if n <= N_MAX]
 M = [4]
 T = [4]
 
@@ -38,8 +107,8 @@ run_exp(LOG_FOLDER, PRIVATE_ROUTE, NUM_EPOCHS, N, M, T, B, PRIV_OUT, PRIV_IN, PU
 
 ## Figure 6 Private
 PRIVATE_ROUTE = True
-N = [1<<20]
-M = [72, 64, 48, 36, 32, 24, 16, 8, 6, 4]
+N = [N_MAX]
+M = [m for m in [72, 64, 48, 36, 32, 24, 16, 8, 6, 4] if m <= M_MAX]
 T = [1]
 
 run_exp(LOG_FOLDER, PRIVATE_ROUTE, NUM_EPOCHS, N, M, T, B, PRIV_OUT, PRIV_IN, PUB_OUT, PUB_IN)