1 /*
 2  * Copyright (c) 2019, 2023, Oracle and/or its affiliates. All rights reserved.
 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
 6  * under the terms of the GNU General Public License version 2 only, as
 7  * published by the Free Software Foundation.  Oracle designates this
 8  * particular file as subject to the "Classpath" exception as provided
 9  * by Oracle in the LICENSE file that accompanied this code.
10  *
11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
16  *
17  * You should have received a copy of the GNU General Public License version
18  * 2 along with this work; if not, write to the Free Software Foundation,
19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20  *
21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22  * or visit www.oracle.com if you need additional information or have any
23  * questions.
24  */
25 package sun.nio.ch;
26 
27 import java.io.IOException;
28 
29 /**
30  * Default PollerProvider for Windows based on wepoll.
31  */
32 class DefaultPollerProvider extends PollerProvider {
33     DefaultPollerProvider() { }
34 
35     @Override
36     int defaultReadPollers(Poller.Mode mode) {
37         assert mode == Poller.Mode.SYSTEM_THREADS;
38         int ncpus = Runtime.getRuntime().availableProcessors();
39         return Math.max(Integer.highestOneBit(ncpus / 8), 1);
40     }
41 
42     @Override
43     int fdValToIndex(int fdVal, int toIndex) {
44         return (fdVal >> 2) & (toIndex - 1);
45     }
46 
47     @Override
48     Poller readPoller(boolean subPoller) throws IOException {
49         assert !subPoller;
50         return new WEPollPoller(true);
51     }
52 
53     @Override
54     Poller writePoller(boolean subPoller) throws IOException {
55         assert !subPoller;
56         return new WEPollPoller(false);
57     }
58 }