From: "H. Peter Anvin" <hpa@zytor.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Stefani Seibold <stefani@seibold.net>,
Greg KH <gregkh@linuxfoundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
X86 ML <x86@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Andi Kleen <ak@linux.intel.com>,
Andrea Arcangeli <aarcange@redhat.com>,
John Stultz <john.stultz@linaro.org>,
Pavel Emelyanov <xemul@parallels.com>,
Cyrill Gorcunov <gorcunov@openvz.org>,
andriy.shevchenko@linux.intel.com,
Martin Runge <Martin.Runge@rohde-schwarz.com>,
Andreas Brief <Andreas.Brief@rohde-schwarz.com>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 3/3] x86, vdso32: handle 32 bit vDSO larger one page
Date: Thu, 13 Mar 2014 12:01:58 -0700 [thread overview]
Message-ID: <532200A6.7060608@zytor.com> (raw)
In-Reply-To: <CALCETrXjJeXqJj3muJhfNeiQ7Te+8WSow+LtjKPM9dySfDtbaA@mail.gmail.com>
On 03/13/2014 11:32 AM, Andy Lutomirski wrote:
>
> I don't recall anyone suggesting keeping the name. CONFIG_COMPAT_VDSO
> will henceforth be a silly name, since the "compat" mode won't have a
> vdso.
>
Linus suggested it:
> What might be acceptable then is to just keep the old config name, and
> if the COMPAT_VDSO config is enabled, you just disable the non-compat
> vdso. At least that way, presumably any opensuse people would have
> their kernel config continue working.
...
> The consensus was that the default should be no vdso, right? My most
> recent patchset calls it CONFIG_ENABLE_VDSO32_BY_DEFAULT and defaults
> to n.
On any practical system, the vdso needs to be turned on -- the syscall
performance difference is very significant.
>> It is important that anyone who actually cares about performance unsets
>> the option.
>
> Should there be a warning at startup if the option is set?
Possibly. Not sure if anyone will read it.
-hpa
next prev parent reply other threads:[~2014-03-13 19:02 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-12 22:51 [PATCH 0/3] Improve 32 bit vDSO time Stefani Seibold
2014-03-12 22:51 ` [PATCH 1/3] x86, vdso32: undef CONFIG_OPTIMIZE_INLINING and CONFIG_X86_PPRO_FENCE Stefani Seibold
2014-03-12 22:51 ` [PATCH 2/3] x86, vdso32: remove vsyscall_32.c Stefani Seibold
2014-03-12 22:51 ` [PATCH 3/3] x86, vdso32: handle 32 bit vDSO larger one page Stefani Seibold
2014-03-12 22:58 ` H. Peter Anvin
2014-03-12 22:59 ` Andy Lutomirski
2014-03-13 15:53 ` H. Peter Anvin
2014-03-13 17:28 ` Andy Lutomirski
2014-03-13 18:08 ` H. Peter Anvin
2014-03-13 18:21 ` H. Peter Anvin
2014-03-13 18:32 ` Andy Lutomirski
2014-03-13 19:01 ` H. Peter Anvin [this message]
[not found] ` <CA+55aFyOp6V_tE-sXKVi+=6yVwHQb0sLWSNbk=N7KbhBrx9QhA@mail.gmail.com>
[not found] ` <CA+55aFyCSL==4Ff4JT3uFKN_28mz92ef1L67-4OUGqHZ8HXUhg@mail.gmail.com>
2014-03-13 19:13 ` Andy Lutomirski
[not found] ` <CA+55aFwDn3zA0gEn2r3nJVPWuv-pLYyrj4=8_gt1xFTd2g_Dwg@mail.gmail.com>
2014-03-13 19:33 ` H. Peter Anvin
[not found] ` <CA+55aFxWsm=P5h1o=BNrwkcy2ZadFsVxpegxJ0rskPVcmo_Ljw@mail.gmail.com>
2014-03-13 19:58 ` H. Peter Anvin
2014-03-13 21:00 ` Andi Kleen
2014-03-13 21:04 ` H. Peter Anvin
2014-03-13 21:10 ` Andi Kleen
2014-03-13 21:48 ` Linus Torvalds
2014-03-18 14:22 ` OT: " Hans-Peter Jansen
2014-03-13 19:35 ` Andy Lutomirski
2014-03-12 22:56 ` [PATCH 0/3] Improve 32 bit vDSO time Andy Lutomirski
2014-03-12 23:11 ` stefani
2014-03-13 3:48 ` H. Peter Anvin
2014-03-13 8:11 ` Stefani Seibold
2014-03-13 22:08 ` H. Peter Anvin
2014-03-14 6:24 ` Stefani Seibold
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