Mercurial > hg > nginx-quic
view src/core/ngx_cpuinfo.c @ 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> |
---|---|
date | Fri, 24 Dec 2021 18:13:51 +0300 |
parents | d620f497c50f |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #if (( __i386__ || __amd64__ ) && ( __GNUC__ || __INTEL_COMPILER )) static ngx_inline void ngx_cpuid(uint32_t i, uint32_t *buf); #if ( __i386__ ) static ngx_inline void ngx_cpuid(uint32_t i, uint32_t *buf) { /* * we could not use %ebx as output parameter if gcc builds PIC, * and we could not save %ebx on stack, because %esp is used, * when the -fomit-frame-pointer optimization is specified. */ __asm__ ( " mov %%ebx, %%esi; " " cpuid; " " mov %%eax, (%1); " " mov %%ebx, 4(%1); " " mov %%edx, 8(%1); " " mov %%ecx, 12(%1); " " mov %%esi, %%ebx; " : : "a" (i), "D" (buf) : "ecx", "edx", "esi", "memory" ); } #else /* __amd64__ */ static ngx_inline void ngx_cpuid(uint32_t i, uint32_t *buf) { uint32_t eax, ebx, ecx, edx; __asm__ ( "cpuid" : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (i) ); buf[0] = eax; buf[1] = ebx; buf[2] = edx; buf[3] = ecx; } #endif /* auto detect the L2 cache line size of modern and widespread CPUs */ void ngx_cpuinfo(void) { u_char *vendor; uint32_t vbuf[5], cpu[4], model; vbuf[0] = 0; vbuf[1] = 0; vbuf[2] = 0; vbuf[3] = 0; vbuf[4] = 0; ngx_cpuid(0, vbuf); vendor = (u_char *) &vbuf[1]; if (vbuf[0] == 0) { return; } ngx_cpuid(1, cpu); if (ngx_strcmp(vendor, "GenuineIntel") == 0) { switch ((cpu[0] & 0xf00) >> 8) { /* Pentium */ case 5: ngx_cacheline_size = 32; break; /* Pentium Pro, II, III */ case 6: ngx_cacheline_size = 32; model = ((cpu[0] & 0xf0000) >> 8) | (cpu[0] & 0xf0); if (model >= 0xd0) { /* Intel Core, Core 2, Atom */ ngx_cacheline_size = 64; } break; /* * Pentium 4, although its cache line size is 64 bytes, * it prefetches up to two cache lines during memory read */ case 15: ngx_cacheline_size = 128; break; } } else if (ngx_strcmp(vendor, "AuthenticAMD") == 0) { ngx_cacheline_size = 64; } } #else void ngx_cpuinfo(void) { } #endif