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[PATCH] x86: Don't include <x86intrin.h>
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Florian Weimer <fw at deneb dot enyo dot de>
- Cc: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>, GNU C Library <libc-alpha at sourceware dot org>
- Date: Sat, 20 Oct 2018 18:11:39 -0700
- Subject: [PATCH] x86: Don't include <x86intrin.h>
On 10/20/18, H.J. Lu <firstname.lastname@example.org> wrote:
> On 10/20/18, Florian Weimer <email@example.com> wrote:
>> * Florian Weimer:
>>> I'm trying to remove the #include <hp-timing.h> from
>>> <libc-internal.h>, but I don't know how hard this will be.
>> That doesn't help. It's pulled in via <tls.h> and <descr.h> as well.
>> We would need a separate <hp_timing_t.h> header file to avoid that
>> because hp_timing_t is required in a few central places (thread
>> descriptor and link map).
> Please try this.
It is not about GCC 6. GCC 8 has the same issue. Here is the updated
From 157f63aef12d8f6abe62996638903c483306fc6a Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <firstname.lastname@example.org>
Date: Sat, 20 Oct 2018 15:22:01 -0700
Subject: [PATCH] x86: Don't include <x86intrin.h>
Use __builtin_ia32_rdtsc directly since including <x86intrin.h> makes
building glibc very slow. On Intel Core i5-6260U, this patch reduces
x86-64 build time from 8 minutes 33 seconds to 3 minutes 48 seconds
with "make -j4" and GCC 8.2.1.
* sysdeps/x86/hp-timing.h: Don't include <x86intrin.h>.
(HP_TIMING_NOW): Replace _rdtsc with __builtin_ia32_rdtsc.
sysdeps/x86/hp-timing.h | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/sysdeps/x86/hp-timing.h b/sysdeps/x86/hp-timing.h
index 1c20e9d828..77a1360748 100644
@@ -22,8 +22,6 @@
#if MINIMUM_ISA == 686 || MINIMUM_ISA == 8664
-# include <x86intrin.h>
/* We always assume having the timestamp register. */
# define HP_TIMING_AVAIL (1)
# define HP_SMALL_TIMING_AVAIL (1)
@@ -38,8 +36,11 @@ typedef unsigned long long int hp_timing_t;
might not be 100% accurate since there might be some more instructions
running in this moment. This could be changed by using a barrier like
'cpuid' right before the `rdtsc' instruciton. But we are not interested
- in accurate clock cycles here so we don't do this. */
-# define HP_TIMING_NOW(Var) ((Var) = _rdtsc ())
+ in accurate clock cycles here so we don't do this.
+ NB: Use __builtin_ia32_rdtsc directly since including <x86intrin.h>
+ makes building glibc very slow. */
+# define HP_TIMING_NOW(Var) ((Var) = __builtin_ia32_rdtsc ())
# include <hp-timing-common.h>