Mercurial > hg > nginx-quic
annotate src/core/ngx_crc.h @ 8759:56dec0d4e5b1 quic
QUIC: avoid excessive buffer allocations in stream output.
Previously, when a few bytes were send to a QUIC stream by the application, a
4K buffer was allocated for these bytes. Then a STREAM frame was created and
that entire buffer was used as data for that frame. The frame with the buffer
were in use up until the frame was acked by client. Meanwhile, when more
bytes were send to the stream, more buffers were allocated and assigned as
data to newer STREAM frames. In this scenario most buffer memory is unused.
Now the unused part of the stream output buffer is available for further
stream output while earlier parts of the buffer are waiting to be acked.
This is achieved by splitting the output buffer.
author | Roman Arutyunyan <arut@nginx.com> |
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date | Fri, 24 Dec 2021 18:13:51 +0300 |
parents | d620f497c50f |
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1 |
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2 /* |
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3 * Copyright (C) Igor Sysoev |
4412 | 4 * Copyright (C) Nginx, Inc. |
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5 */ |
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8 #ifndef _NGX_CRC_H_INCLUDED_ |
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9 #define _NGX_CRC_H_INCLUDED_ |
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792 | 12 #include <ngx_config.h> |
13 #include <ngx_core.h> | |
14 | |
15 | |
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16 /* 32-bit crc16 */ |
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776 | 18 static ngx_inline uint32_t |
789 | 19 ngx_crc(u_char *data, size_t len) |
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20 { |
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21 uint32_t sum; |
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23 for (sum = 0; len; len--) { |
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25 /* |
776 | 26 * gcc 2.95.2 x86 and icc 7.1.006 compile |
27 * that operator into the single "rol" opcode, | |
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28 * msvc 6.0sp2 compiles it into four opcodes. |
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29 */ |
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30 sum = sum >> 1 | sum << 31; |
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31 |
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32 sum += *data++; |
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33 } |
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35 return sum; |
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36 } |
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38 |
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39 #endif /* _NGX_CRC_H_INCLUDED_ */ |