From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: Florian Weimer <fweimer@redhat.com>, Arnd Bergmann <arnd@arndb.de>
Cc: Alistair Francis <alistair.francis@wdc.com>,
GNU C Library <libc-alpha@sourceware.org>,
Palmer Dabbelt <palmer@sifive.com>,
macro@wdc.com, Zong Li <zongbox@gmail.com>,
Alistair Francis <alistair23@gmail.com>
Subject: Re: [RFC v3 04/23] sysdeps/clock_gettime: Use clock_gettime64 if avaliable
Date: Thu, 18 Jul 2019 15:10:01 -0300 [thread overview]
Message-ID: <5460442e-f586-b493-dd20-68761fb4e346@linaro.org> (raw)
In-Reply-To: <87y30v3gcv.fsf@oldenburg2.str.redhat.com>
On 18/07/2019 05:18, Florian Weimer wrote:
> * Arnd Bergmann:
>
>> I have two ideas for how that could be done:
>>
>> - When building for a minimum kernel version of 5.1, don't
>> fall back to __vdso_clock_gettime() or syscall(__NR_clock_gettime)
>> but use the slow path for __clock_gettime64() if the vdso doesn't
>> work.
>
> Assuming that clock_gettime64 support is available, yes.
>
>> - if __vdso_clock_gettime64() is unavailable and __vdso_clock_gettime()
>> returns negative seconds, fall back to syscall(__NR_clock_gettime).
>
> I don't want to do anything like this. I expect that some of us will
> eventually use time namespaces to keep programs running (with incorrect
> time). If we make glibc itself time-sensitive, then things will get
> horribly complex.
>
>> Would either of those meet your requirements?
>
> I don't have requirements. I just want something that has limited
> impact on 64-bit architectures. I don't think probing at startup is too
> bad, actually.
I hope that my vDSO refactor patchset [1] may simplify the support.
For the patchset it just a matter of define the expected vDSO symbol
name (HAVE_CLOCK_GETTIME_VSYSCALL for time32), and then
{INLINE,INTERNAL}_VSYSCALL will check, demangle, call, and fallback
to syscall.
I would expect that for time64_t it would be a matter to just add
a new define, HAVE_CLOCK_GETTIME64_VSYSCALL, where each architecture
would define if were the case.
[1] https://sourceware.org/ml/libc-alpha/2019-06/msg00344.html
next prev parent reply other threads:[~2019-07-18 18:10 UTC|newest]
Thread overview: 127+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-17 0:08 [RFC v3 00/23] RISC-V glibc port for the 32-bit Alistair Francis
2019-07-17 0:08 ` [RFC v3 01/23] sysdeps/nanosleep: Use clock_nanosleep_time64 if avaliable Alistair Francis
2019-07-17 5:16 ` Florian Weimer
2019-07-19 17:25 ` Alistair Francis
2019-07-20 14:24 ` Stepan Golosunov
2019-07-22 21:14 ` Alistair Francis
2019-07-17 0:08 ` [RFC v3 02/23] sysdeps/gettimeofday: Use clock_gettime64 " Alistair Francis
2019-07-17 7:09 ` Florian Weimer
2019-07-20 3:20 ` Rich Felker
2019-07-25 20:54 ` Joseph Myers
2019-07-17 12:43 ` Lukasz Majewski
2019-07-17 12:48 ` Lukasz Majewski
2019-07-19 22:26 ` Alistair Francis
2019-07-17 0:08 ` [RFC v3 03/23] sysdeps/wait: Use waitid " Alistair Francis
2019-07-17 5:31 ` Florian Weimer
2019-07-19 17:49 ` Alistair Francis
2019-07-22 15:58 ` Florian Weimer
2019-07-22 21:02 ` Alistair Francis
2019-07-21 4:03 ` Rich Felker
2019-07-21 4:20 ` Rich Felker
2019-07-21 11:59 ` Eric W. Biederman
2019-07-21 22:59 ` Rich Felker
2019-07-21 7:57 ` Arnd Bergmann
2019-07-21 12:15 ` Eric W. Biederman
2019-07-21 12:28 ` Christian Brauner
2019-07-21 14:30 ` Arnd Bergmann
2019-07-21 15:45 ` Eric W. Biederman
2019-07-21 17:05 ` Arnd Bergmann
2019-07-21 17:16 ` Linus Torvalds
2019-07-21 21:40 ` Eric W. Biederman
2019-07-21 23:23 ` Rich Felker
2019-07-23 0:00 ` Eric W. Biederman
2019-07-23 8:12 ` Arnd Bergmann
2019-07-23 8:28 ` Christian Brauner
2019-07-23 8:45 ` Arnd Bergmann
2019-07-25 0:04 ` Alistair Francis
2019-07-25 4:40 ` Rich Felker
2019-07-25 13:15 ` Arnd Bergmann
2019-07-25 16:06 ` Christian Brauner
2019-07-25 17:14 ` Eric W. Biederman
2019-07-25 17:30 ` Christian Brauner
2019-08-13 22:22 ` Alistair Francis
2019-08-13 23:11 ` Rich Felker
2019-08-14 5:07 ` Christian Brauner
2019-08-14 11:38 ` [PATCH v1 0/1] waitid: process group enhancement christian.brauner
2019-08-14 11:38 ` [PATCH v1 1/1] waitid: Add support for waiting for the current process group christian.brauner
2019-08-14 12:29 ` Oleg Nesterov
2019-08-14 12:45 ` Christian Brauner
2019-08-14 12:50 ` Oleg Nesterov
2019-08-14 12:53 ` Christian Brauner
2019-08-14 13:07 ` [PATCH v2 0/1] waitid: process group enhancement Christian Brauner
2019-08-14 13:07 ` [PATCH v2 1/1] waitid: Add support for waiting for the current process group Christian Brauner
2019-08-14 14:19 ` Oleg Nesterov
2019-08-14 14:35 ` Christian Brauner
2019-08-14 15:27 ` Oleg Nesterov
2019-08-14 15:30 ` Christian Brauner
2019-08-14 15:43 ` [PATCH v3 0/1] waitid: process group enhancement Christian Brauner
2019-08-14 15:44 ` [PATCH v3 1/1] waitid: Add support for waiting for the current process group Christian Brauner
2019-08-14 16:09 ` Oleg Nesterov
2019-08-14 16:15 ` Christian Brauner
2019-08-14 16:34 ` Christian Brauner
2019-08-14 16:55 ` Rich Felker
2019-08-14 17:02 ` Christian Brauner
2019-08-14 17:06 ` Linus Torvalds
2019-08-14 18:00 ` Rich Felker
2019-08-14 20:50 ` Christian Brauner
2019-08-14 15:58 ` [PATCH v3 0/1] waitid: process group enhancement Rich Felker
2019-08-14 16:13 ` Christian Brauner
2019-07-26 23:35 ` [RFC v3 03/23] sysdeps/wait: Use waitid if avaliable Alistair Francis
2019-07-17 0:08 ` [RFC v3 04/23] sysdeps/clock_gettime: Use clock_gettime64 " Alistair Francis
2019-07-17 5:38 ` Florian Weimer
2019-07-17 8:04 ` Arnd Bergmann
2019-07-17 8:44 ` Florian Weimer
2019-07-17 9:10 ` Arnd Bergmann
2019-07-17 15:16 ` Florian Weimer
2019-07-18 7:38 ` Arnd Bergmann
2019-07-18 8:18 ` Florian Weimer
2019-07-18 9:14 ` Arnd Bergmann
2019-07-18 18:10 ` Adhemerval Zanella [this message]
2019-07-19 21:03 ` Alistair Francis
2019-07-17 7:03 ` Andreas Schwab
2019-07-17 12:37 ` Lukasz Majewski
2019-07-17 0:08 ` [RFC v3 05/23] sysdeps/timespec_get: " Alistair Francis
2019-07-17 5:08 ` Florian Weimer
2019-07-17 7:59 ` Arnd Bergmann
2019-07-17 8:11 ` Florian Weimer
2019-07-17 8:23 ` Arnd Bergmann
2019-07-17 8:41 ` Florian Weimer
2019-07-17 8:54 ` Arnd Bergmann
2019-07-25 20:14 ` Joseph Myers
2019-07-17 12:22 ` Lukasz Majewski
2019-07-17 0:08 ` [RFC v3 06/23] Documentation for the RISC-V 32-bit port Alistair Francis
2019-07-17 0:08 ` [RFC v3 07/23] RISC-V: Use 64-bit time_t and off_t for RV32 and RV64 Alistair Francis
2019-07-17 8:27 ` Arnd Bergmann
2019-07-17 22:39 ` Alistair Francis
2019-07-18 7:41 ` Arnd Bergmann
2019-07-18 17:36 ` Alistair Francis
2019-07-19 6:44 ` Arnd Bergmann
2019-07-19 17:02 ` Alistair Francis
2019-07-17 0:09 ` [RFC v3 08/23] RISC-V: define __NR_futex as __NR_futex_time64 for 32-bit Alistair Francis
2019-07-17 0:09 ` [RFC v3 09/23] RISC-V: define __NR_* as __NR_*_time64/64 " Alistair Francis
2019-07-17 0:09 ` [RFC v3 10/23] RISC-V: define __NR_clock_getres as __NR_*_time64 " Alistair Francis
2019-07-17 0:09 ` [RFC v3 11/23] RISC-V: define __vdso_clock_getres as __vdso_clock_getres_time64 " Alistair Francis
2019-07-17 0:09 ` [RFC v3 12/23] RISC-V: define __vdso_clock_gettime as __vdso_clock_gettime64 " Alistair Francis
2019-07-17 8:16 ` Arnd Bergmann
2019-07-19 17:15 ` Alistair Francis
2019-07-17 0:09 ` [RFC v3 13/23] RISC-V: Use 64-bit timespec in clock_gettime vdso calls Alistair Francis
2019-07-17 8:13 ` Arnd Bergmann
2019-07-17 0:09 ` [RFC v3 14/23] RISC-V: Support dynamic loader for the 32-bit Alistair Francis
2019-07-17 0:09 ` [RFC v3 15/23] RISC-V: Add path of library directories " Alistair Francis
2019-07-17 12:20 ` Florian Weimer
2019-07-17 0:09 ` [RFC v3 16/23] RISC-V: The ABI implementation " Alistair Francis
2019-07-17 0:09 ` [RFC v3 17/23] RISC-V: Hard float support for the 32 bit Alistair Francis
2019-07-17 0:09 ` [RFC v3 18/23] RISC-V: Regenerate ULPs of RISC-V Alistair Francis
2019-07-17 0:09 ` [RFC v3 19/23] RISC-V: Add ABI lists Alistair Francis
2019-07-17 0:09 ` [RFC v3 20/23] RISC-V: Build Infastructure for the 32-bit Alistair Francis
2019-07-17 0:09 ` [RFC v3 21/23] RISC-V: Fix llrint and llround missing exceptions on RV32 Alistair Francis
2019-07-17 12:22 ` Florian Weimer
2019-07-17 22:32 ` Alistair Francis
2019-07-17 0:09 ` [RFC v3 22/23] Add RISC-V 32-bit target to build-many-glibcs.py Alistair Francis
2019-07-17 0:09 ` [RFC v3 23/23] RISC-V: Use 64-bit vdso syscalls Alistair Francis
2019-07-17 5:33 ` Florian Weimer
2019-07-17 8:02 ` Arnd Bergmann
2019-07-17 22:23 ` Alistair Francis
2019-07-17 23:42 ` Alistair Francis
2019-07-18 0:01 ` Alistair Francis
2019-07-19 17:14 ` [RFC v3 00/23] RISC-V glibc port for the 32-bit Alistair Francis
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://www.gnu.org/software/libc/involved.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5460442e-f586-b493-dd20-68761fb4e346@linaro.org \
--to=adhemerval.zanella@linaro.org \
--cc=alistair.francis@wdc.com \
--cc=alistair23@gmail.com \
--cc=arnd@arndb.de \
--cc=fweimer@redhat.com \
--cc=libc-alpha@sourceware.org \
--cc=macro@wdc.com \
--cc=palmer@sifive.com \
--cc=zongbox@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).