Ben Maurer
ef1e94eee2
On Linux, fadvise forces unwritten pages to be flushed to disk before returning. This means that under heavy disk IO, all threads could be waiting on the fadvise call. This diff uses atomic operations to ensure that only one thread can do IO at any given time. In addition, it makes any fadvise calls tail the end of the file by 1 MB. This reduces the chance that fadvise will trigger IO at all.
77 linhas
2.4 KiB
C++
77 linhas
2.4 KiB
C++
/*
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+----------------------------------------------------------------------+
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| HipHop for PHP |
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+----------------------------------------------------------------------+
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| Copyright (c) 2010-2013 Facebook, Inc. (http://www.facebook.com) |
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+----------------------------------------------------------------------+
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| This source file is subject to version 3.01 of the PHP license, |
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| that is bundled with this package in the file LICENSE, and is |
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| available through the world-wide-web at the following url: |
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| http://www.php.net/license/3_01.txt |
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| If you did not receive a copy of the PHP license and are unable to |
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| obtain it through the world-wide-web, please send a note to |
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| license@php.net so we can mail you a copy immediately. |
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+----------------------------------------------------------------------+
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*/
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#include "hphp/util/logger.h"
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#include "gtest/gtest.h"
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namespace HPHP {
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class MockLogFileFlusher : public LogFileFlusher {
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public:
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MockLogFileFlusher() : last_flush(0) {}
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off_t last_flush;
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protected:
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void dropCache(int fd, off_t off) {
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last_flush = off;
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}
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};
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static void doWrite(LogFileFlusher* flusher, int fd, int bytes) {
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char* buf = new char[bytes];
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write(fd, buf, bytes);
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delete[] buf;
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flusher->recordWriteAndMaybeDropCaches(fd, bytes);
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}
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TEST(LogFileFlusherTest, flush) {
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MockLogFileFlusher flusher;
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LogFileFlusher::DropCacheChunkSize = 1 << 19;
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ASSERT_EQ(LogFileFlusher::kDropCacheTail, 1 << 20);
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char tmpl[] = "/tmp/LogFileFlusherTest.XXXXXX";
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int fd = mkstemp(tmpl);
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ASSERT_NE(fd, 0);
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unlink (tmpl);
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// 100 bytes written, not enough to flush
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doWrite(&flusher, fd, 100);
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EXPECT_EQ(flusher.last_flush, 0);
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// 512KB written, but file is not 1 MB large yet so no fadvise
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doWrite(&flusher, fd, (1 << 19));
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EXPECT_EQ(flusher.last_flush, 0);
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// Another 512KB, after one more byte a fadvise will be called
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doWrite(&flusher, fd, (1 << 19));
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EXPECT_EQ(flusher.last_flush, 0);
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// fadvise called
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doWrite(&flusher, fd, 1);
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EXPECT_EQ(flusher.last_flush, 101);
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// Almost ready for another flush
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doWrite(&flusher, fd, (1 << 19));
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EXPECT_EQ(flusher.last_flush, 101);
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// Another flush occurs
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doWrite(&flusher, fd, 1);
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EXPECT_EQ(flusher.last_flush, (1 << 19) + 100 + 2);
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}
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}
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