[PATCH nginx v2] remove ngx_cpuinfo, use sysconf or define
Vladimir Homutov
vl at nginx.com
Thu Jan 16 14:43:09 UTC 2020
On Fri, Jan 03, 2020 at 02:39:29PM -0800, Joe Konno wrote:
> # HG changeset patch
> # User Joe Konno <joe.konno at intel.com>
> # Date 1578075036 28800
> # Fri Jan 03 10:10:36 2020 -0800
> # Node ID b66ee34cea2f539bb8ce4986d6bd332f75ee06b6
> # Parent f1720934c45be1c6469841a55d1f31fe9a630c85
> remove ngx_cpuinfo, use sysconf or define
>
> Function ngx_cpuinfo() is used to (sub-optimally) determine the value of
> ngx_cacheline_size on x86 hardware. On hardware running Linux, there may be a
> sysconf call that correctly reports the cache line size using architecturally
> appropriate methods-- for x86 hardware, the CPUID instruction.
>
> Therefore, ngx_cpuinfo is no longer needed. If said sysconf call is
> unavailable, set ngx_cachline_size to defined NGX_CPU_CACHE_LINE, the value of
> which is determined at configure time.
>
> Signed-off-by: Joe Konno <joe.konno at intel.com>
>
> diff -r f1720934c45b -r b66ee34cea2f auto/sources
> --- a/auto/sources Fri Dec 27 19:43:01 2019 +0300
> +++ b/auto/sources Fri Jan 03 10:10:36 2020 -0800
> @@ -71,7 +71,6 @@
> src/core/ngx_cycle.c \
> src/core/ngx_spinlock.c \
> src/core/ngx_rwlock.c \
> - src/core/ngx_cpuinfo.c \
> src/core/ngx_conf_file.c \
> src/core/ngx_module.c \
> src/core/ngx_resolver.c \
> diff -r f1720934c45b -r b66ee34cea2f src/core/ngx_core.h
> --- a/src/core/ngx_core.h Fri Dec 27 19:43:01 2019 +0300
> +++ b/src/core/ngx_core.h Fri Jan 03 10:10:36 2020 -0800
> @@ -102,7 +102,6 @@
> #define ngx_max(val1, val2) ((val1 < val2) ? (val2) : (val1))
> #define ngx_min(val1, val2) ((val1 > val2) ? (val2) : (val1))
>
> -void ngx_cpuinfo(void);
>
> #if (NGX_HAVE_OPENAT)
> #define NGX_DISABLE_SYMLINKS_OFF 0
> diff -r f1720934c45b -r b66ee34cea2f src/core/ngx_cpuinfo.c
> --- a/src/core/ngx_cpuinfo.c Fri Dec 27 19:43:01 2019 +0300
> +++ /dev/null Thu Jan 01 00:00:00 1970 +0000
> @@ -1,139 +0,0 @@
> -
> -/*
> - * 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
> diff -r f1720934c45b -r b66ee34cea2f src/os/unix/ngx_posix_init.c
> --- a/src/os/unix/ngx_posix_init.c Fri Dec 27 19:43:01 2019 +0300
> +++ b/src/os/unix/ngx_posix_init.c Fri Jan 03 10:10:36 2020 -0800
> @@ -51,10 +51,20 @@
> }
>
> ngx_pagesize = getpagesize();
> - ngx_cacheline_size = NGX_CPU_CACHE_LINE;
>
> for (n = ngx_pagesize; n >>= 1; ngx_pagesize_shift++) { /* void */ }
>
> +#if (NGX_HAVE_LEVEL1_DCACHE_LINESIZE)
> + size = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);
> + if (size > 0) {
> + ngx_cacheline_size = size;
> + } else {
> + ngx_cacheline_size = NGX_CPU_CACHE_LINE;
> + }
> +#else
> + ngx_cacheline_size = NGX_CPU_CACHE_LINE;
> +#endif
> +
> #if (NGX_HAVE_SC_NPROCESSORS_ONLN)
> if (ngx_ncpu == 0) {
> ngx_ncpu = sysconf(_SC_NPROCESSORS_ONLN);
> @@ -65,15 +75,6 @@
> ngx_ncpu = 1;
> }
>
> -#if (NGX_HAVE_LEVEL1_DCACHE_LINESIZE)
> - size = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);
> - if (size > 0) {
> - ngx_cacheline_size = size;
> - }
> -#endif
> -
> - ngx_cpuinfo();
> -
> if (getrlimit(RLIMIT_NOFILE, &rlmt) == -1) {
> ngx_log_error(NGX_LOG_ALERT, log, errno,
> "getrlimit(RLIMIT_NOFILE) failed");
>
Thank you for sharing!
Removing ngx_cpuinfo() doesn't look correct: by doing this you deprive
non-Linux systems (BSDs, windows and some others) support for CPU detection.
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