From: Jonathan Wakely <jwakely@redhat.com>
To: Thiago Macieira <thiago.macieira@intel.com>
Cc: Ville Voutilainen <ville.voutilainen@gmail.com>,
Thomas Rodgers <trodgers@redhat.com>,
libstdc++ <libstdc++@gcc.gnu.org>
Subject: Re: C++2a synchronisation inefficient in GCC 11
Date: Wed, 3 Mar 2021 17:14:59 +0000 [thread overview]
Message-ID: <YD/EEzKZqyPsflTy@redhat.com> (raw)
In-Reply-To: <5422241.zR2LmqfNYo@tjmaciei-mobl1>
On 03/03/21 09:07 -0800, Thiago Macieira via Libstdc++ wrote:
>On Wednesday, 3 March 2021 06:30:20 PST Jonathan Wakely wrote:
>> Yes, exactly. They could still do that if some additional option/macro
>> was needed to get to those new facilities though.
>>
>> My concern is that if we add a new "I know what I'm doing" option,
>> everybody defines it (because that's what blog posts and youtube
>> videos and conference talks tell them to do, because that gives them
>> the new shiny things) and then it just becomes a default.
>>
>> Maybe Qt wouldn't define it, but plenty would.
>
>Well, if you define the "void warranty" option and you break things, you get
>to keep both pieces.
>
>Another option is to fiddle with the include path.
>
>$ gcc -v -E -xc++ /dev/null
>Using built-in specs.
>[...]
>#include <...> search starts here:
> /usr/lib64/gcc/x86_64-generic-linux/10/../../../../include/c++/10
> /usr/lib64/gcc/x86_64-generic-linux/10/../../../../include/c++/10/x86_64-
>generic-linux
> /usr/lib64/gcc/x86_64-generic-linux/10/../../../../include/c++/10/backward
> /usr/lib64/gcc/x86_64-generic-linux/10/include
> /usr/local/include
> /usr/lib64/gcc/x86_64-generic-linux/10/include-fixed
> /usr/include
>
>That "backward" has always got me thinking. What if we had a command-line
>option like -fexperimental-c++ option that added the $CXXROOT/experimental
We already have an experimental sub-dir for TS headers, so you need to
pick another name. Otherwise <vector> and <experimental/vector> get
mixed up.
next prev parent reply other threads:[~2021-03-03 17:15 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-25 22:50 Thiago Macieira
2021-02-26 11:19 ` Jonathan Wakely
2021-02-26 17:37 ` Thiago Macieira
2021-02-26 18:29 ` Jonathan Wakely
2021-02-26 19:30 ` Ville Voutilainen
2021-02-26 21:17 ` Jonathan Wakely
2021-02-26 21:18 ` Ville Voutilainen
2021-02-26 21:39 ` Jonathan Wakely
2021-02-26 18:47 ` Ville Voutilainen
2021-02-26 23:53 ` Thiago Macieira
2021-02-26 23:58 ` Ville Voutilainen
2021-02-27 0:11 ` Thiago Macieira
2021-02-27 0:18 ` Ville Voutilainen
2021-02-27 0:36 ` Thiago Macieira
2021-02-27 0:44 ` Ville Voutilainen
2021-02-27 0:53 ` Thiago Macieira
2021-02-27 1:03 ` Ville Voutilainen
2021-03-03 14:30 ` Jonathan Wakely
2021-03-03 17:07 ` Thiago Macieira
2021-03-03 17:14 ` Jonathan Wakely [this message]
2021-02-27 0:22 ` Marc Glisse
2021-02-27 0:30 ` Ville Voutilainen
2021-02-27 0:43 ` Thiago Macieira
2021-03-03 14:24 ` Jonathan Wakely
2021-03-03 17:12 ` Thiago Macieira
2021-02-26 15:59 ` [PATCH 1/5] std::latch: reduce internal implementation from ptrdiff_t to int Thiago Macieira
2021-02-26 15:59 ` [PATCH 2/5] Atomic __platform_wait: accept any 32-bit type, not just int Thiago Macieira
2021-03-03 14:34 ` Jonathan Wakely
2021-03-03 16:21 ` Jonathan Wakely
2021-03-03 17:27 ` Thiago Macieira
2021-03-03 17:34 ` Ville Voutilainen
2021-03-03 17:41 ` Jonathan Wakely
2021-02-26 15:59 ` [PATCH 3/5] std::__atomic_wait: don't use __detail::__waiter with futex Thiago Macieira
2021-02-26 15:59 ` [PATCH 4/5] barrier: use int instead of unsigned char for the phase state Thiago Macieira
2021-02-28 15:05 ` Hans-Peter Nilsson
2021-03-01 16:28 ` Thomas Rodgers
2021-03-01 17:24 ` Thiago Macieira
2021-03-01 17:38 ` Thomas Rodgers
2021-03-01 17:40 ` Thomas Rodgers
2021-03-01 18:06 ` Thiago Macieira
2021-03-01 19:08 ` Thomas Rodgers
2021-03-01 18:12 ` Ville Voutilainen
2021-03-01 19:44 ` Thiago Macieira
2021-03-01 20:35 ` Ville Voutilainen
2021-03-01 21:54 ` Thiago Macieira
2021-03-01 22:04 ` Ville Voutilainen
2021-03-01 22:21 ` Thiago Macieira
2021-03-01 22:31 ` Ville Voutilainen
2021-03-01 22:40 ` Thiago Macieira
2021-02-26 15:59 ` [PATCH 5/5] barrier: optimise by not having the hasher in a loop Thiago Macieira
2021-03-03 14:36 ` Jonathan Wakely
2021-02-26 18:14 ` [PATCH 1/5] std::latch: reduce internal implementation from ptrdiff_t to int Andreas Schwab
2021-02-26 19:08 ` Thiago Macieira
2021-02-26 19:31 ` Andreas Schwab
2021-02-27 0:13 ` Thiago Macieira
2021-02-28 21:31 ` Hans-Peter Nilsson
2021-03-01 8:56 ` Richard Biener
2021-03-03 14:56 ` Jonathan Wakely
2021-03-03 15:02 ` Andreas Schwab
2021-03-03 15:10 ` Jonathan Wakely
2021-03-03 15:37 ` Hans-Peter Nilsson
2021-03-01 16:32 ` Thomas Rodgers
2021-03-03 14:34 ` Jonathan Wakely
2021-03-03 17:14 ` Thiago Macieira
2021-03-03 17:18 ` Jonathan Wakely
2021-02-27 1:13 ` C++2a synchronisation inefficient in GCC 11 Thomas Rodgers
2021-02-27 1:29 ` Thomas Rodgers
2021-02-27 3:01 ` Thomas Rodgers
2021-03-01 17:46 ` Thomas Rodgers
2021-03-01 18:00 ` Thiago Macieira
2021-03-01 18:34 ` Thomas Rodgers
2021-03-01 19:11 ` Thiago Macieira
2021-02-27 2:02 ` Ville Voutilainen
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