ceph/src/seastar/include/seastar/core/cacheline.hh

   1 /*
   2  * This file is open source software, licensed to you under the terms
   3  * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
   4  * distributed with this work for additional information regarding copyright
   5  * ownership.  You may not use this file except in compliance with the License.
   6  *
   7  * You may obtain a copy of the License at
   8  *
   9  *   http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing,
  12  * software distributed under the License is distributed on an
  13  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  14  * KIND, either express or implied.  See the License for the
  15  * specific language governing permissions and limitations
  16  * under the License.
  17  */
  18 /*
  19  * Copyright (C) 2017 IBM.
  20  */
  21
  22 #pragma once
  23
  24 #include <cstddef>
  25
  26 namespace seastar {
  27
  28 // Platform-dependent cache line size for alignment and padding purposes.
  29 static constexpr size_t cache_line_size =
  30 #if defined(__x86_64__) || defined(__i386__)
  31     64;
  32 #elif defined(__s390x__) || defined(__zarch__)
  33     256;
  34 #elif defined(__PPC64__)
  35     128;
  36 #elif defined(__aarch64__)
  37     128; // from Linux, may vary among different microarchitetures?
  38 #else
  39 #error "cache_line_size not defined for this architecture"
  40 #endif
  41
  42 }