From: Steven Rostedt <rostedt@goodmis.org>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Boqun Feng <boqun.feng@gmail.com>,
Andy Lutomirski <luto@amacapital.net>,
Dave Watson <davejwatson@fb.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-api <linux-api@vger.kernel.org>,
Paul Turner <pjt@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Russell King <linux@arm.linux.org.uk>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Andrew Hunter <ahh@google.com>, Andi Kleen <andi@firstfloor.org>,
Chris Lameter <cl@linux.com>, Ben Maurer <bmaurer@fb.com>,
Josh Triplett <josh@joshtriplett.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>W
Subject: Re: [RFC PATCH for 4.17 02/21] rseq: Introduce restartable sequences system call (v12)
Date: Thu, 29 Mar 2018 14:07:52 -0400 [thread overview]
Message-ID: <20180329140752.12661138@gandalf.local.home> (raw)
In-Reply-To: <21903915.856.1522346553810.JavaMail.zimbra@efficios.com>
On Thu, 29 Mar 2018 14:02:33 -0400 (EDT)
Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote:
> Currently, anyone using ptrace on a process has pretty much given up all
> hopes of performance. Processes will use rseq to gain performance, not the
> opposite, so this deterioration will be unwelcome.
The ptrace path has nothing to do with ptrace anymore, and probably be
hard to notice the performance hit. You simply set a TIF flag, and on
exit of the syscall it jumps to a path that checks special cases
(tracing system calls being one of them). It's called the ptrace path
because ptrace was the first one to use it (I'm guessing, I haven't
actually looked at the history).
This is used to add any system call checks that are not done during
normal operation. And this certainly falls under that category.
-- Steve
next prev parent reply other threads:[~2018-03-29 18:07 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-27 16:05 [RFC PATCH for 4.17 00/21] Restartable sequences and CPU op vector Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 01/21] uapi headers: Provide types_32_64.h Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 02/21] rseq: Introduce restartable sequences system call (v12) Mathieu Desnoyers
2018-03-28 6:47 ` Boqun Feng
2018-03-28 14:06 ` Mathieu Desnoyers
2018-03-28 14:31 ` Mathieu Desnoyers
2018-03-28 11:19 ` Peter Zijlstra
2018-03-28 14:19 ` Mathieu Desnoyers
2018-03-28 11:22 ` Peter Zijlstra
2018-03-28 14:26 ` Mathieu Desnoyers
2018-03-28 12:29 ` Peter Zijlstra
2018-03-28 12:52 ` Peter Zijlstra
2018-03-28 15:03 ` Mathieu Desnoyers
2018-03-28 16:19 ` Mathieu Desnoyers
2018-03-28 12:50 ` Peter Zijlstra
2018-03-28 14:47 ` Mathieu Desnoyers
2018-03-28 14:59 ` Peter Zijlstra
2018-03-28 15:14 ` Mathieu Desnoyers
2018-03-28 15:28 ` Peter Zijlstra
2018-03-28 15:37 ` Mathieu Desnoyers
2018-03-28 17:49 ` Peter Zijlstra
2018-03-28 20:19 ` Mathieu Desnoyers
2018-03-28 21:25 ` Thomas Gleixner
2018-03-29 13:54 ` Mathieu Desnoyers
2018-03-29 14:23 ` Peter Zijlstra
2018-03-29 15:39 ` Mathieu Desnoyers
2018-03-29 16:24 ` Steven Rostedt
2018-03-29 18:02 ` Mathieu Desnoyers
2018-03-29 18:07 ` Steven Rostedt [this message]
2018-03-29 18:35 ` Mathieu Desnoyers
2018-03-29 18:46 ` Steven Rostedt
2018-03-29 18:47 ` Steven Rostedt
2018-04-01 16:13 ` Alan Cox
2018-04-02 15:03 ` Christopher Lameter
2018-04-02 15:27 ` Paul E. McKenney
2018-04-02 15:33 ` Mathieu Desnoyers
2018-04-03 16:36 ` Mathieu Desnoyers
2018-04-03 20:32 ` Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 03/21] arm: Add restartable sequences support Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 04/21] arm: Wire up restartable sequences system call Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 05/21] x86: Add support for restartable sequences Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 06/21] x86: Wire up restartable sequence system call Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 07/21] powerpc: Add support for restartable sequences Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 08/21] powerpc: Wire up restartable sequences system call Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 09/21] sched: Implement push_task_to_cpu (v2) Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 10/21] cpu_opv: Provide cpu_opv system call (v6) Mathieu Desnoyers
2018-03-28 15:22 ` Peter Zijlstra
2018-03-28 17:54 ` Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 11/21] x86: Wire up cpu_opv system call Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 12/21] powerpc: " Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 13/21] arm: " Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 14/21] selftests: lib.mk: Introduce OVERRIDE_TARGETS Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 15/21] cpu_opv: selftests: Implement selftests (v7) Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 16/21] rseq: selftests: Provide rseq library (v5) Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 17/21] rseq: selftests: Provide percpu_op API Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 18/21] rseq: selftests: Provide basic test Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 19/21] rseq: selftests: Provide basic percpu ops test Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 20/21] rseq: selftests: Provide parametrized tests Mathieu Desnoyers
2018-03-27 16:05 ` [RFC PATCH for 4.17 21/21] rseq: selftests: Provide Makefile, scripts, gitignore Mathieu Desnoyers
2018-03-27 19:09 ` [RFC PATCH for 4.17 00/21] Restartable sequences and CPU op vector Peter Zijlstra
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