bench: more tweaks to run memcached

Signed-off-by: Reto Achermann <achreto@gmail.com>

Author: achreto

kernel/tests/s11_rackscale_benchmarks.rs

@@ -1297,7 +1297,7 @@ fn s11_rackscale_memcached_benchmark_sharded_nros() {
     test.is_multi_node = true;
 
     if !is_smoke {
-        test.shmem_size = MEMCACHED_MEM_SIZE_MB * 2;
+        test.shmem_size = std::cmp::min(MEMCACHED_MEM_SIZE_MB * 2, SHMEM_SIZE);
     }
 
     fn cmd_fn(num_cores: usize, arg: Option<MemcachedShardedConfig>) -> String {
@@ -1321,7 +1321,8 @@ fn s11_rackscale_memcached_benchmark_sharded_nros() {
             8192
         } else {
             // Memory must also be divisible by number of nodes, which could be 1, 2, 3, or 4
-            (2048 + 2 * MEMCACHED_MEM_SIZE_MB) * (((((num_cores + 1) / 2) + 3 - 1) / 3) * 3)
+            (4096 + std::cmp::min(MEMCACHED_MEM_SIZE_MB * 2, SHMEM_SIZE))
+                * (((((num_cores + 1) / 2) + 3 - 1) / 3) * 3)
         }
     }