linux-mips
[Top] [All Lists]

Re: [PATCH 0/3] MIPS vdso and signal delivery optimization (v2)

To: ralf@linux-mips.org
Subject: Re: [PATCH 0/3] MIPS vdso and signal delivery optimization (v2)
From: David Daney <ddaney@caviumnetworks.com>
Date: Fri, 19 Feb 2010 14:08:20 -0800
Cc: linux-mips@linux-mips.org
In-reply-to: <4B7DF12B.6090802@caviumnetworks.com>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <1266538385-29088-1-git-send-email-ddaney@caviumnetworks.com> <4B7DF12B.6090802@caviumnetworks.com>
Sender: linux-mips-bounce@linux-mips.org
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.7) Gecko/20100120 Fedora/3.0.1-1.fc12 Thunderbird/3.0.1
On 02/18/2010 06:02 PM, David Daney wrote:
Well this patch set does cause gdb to no longer be able to generate
stack traces from signal handlers, but that just means gdb needs to be
fixed. We will work on that next.

Attached is the corresponding gdb patch. I will push it into the upstream gdb.

David Daney



libgcc can unwind through signal handlers both with and without the patch.

David Daney


On 02/18/2010 04:13 PM, David Daney wrote:
This patch set creates a vdso and moves the signal
trampolines to it from their previous home on the stack.

In the original patch set:
http://www.linux-mips.org/cgi-bin/mesg.cgi?a=linux-mips&i=49EE3B0F.3040506%40caviumnetworks.com


I stated:

Tested with a 64-bit kernel on a Cavium Octeon cn3860 where I have the
following results from lmbench2:

Before:
n64 - Signal handler overhead: 14.517 microseconds
n32 - Signal handler overhead: 14.497 microseconds
o32 - Signal handler overhead: 16.637 microseconds

After:

n64 - Signal handler overhead: 7.935 microseconds
n32 - Signal handler overhead: 7.334 microseconds
o32 - Signal handler overhead: 8.628 microsecond

All that is still true.

Improvements from the first version:

* Compiles and runs in 32-bit kernels (on qemu at least).

* Updated for linux-queue based 2.6.33-rc8

David Daney (3):
MIPS: Add SYSCALL to uasm.
MIPS: Preliminary vdso.
MIPS: Move signal trampolines off of the stack.

arch/mips/include/asm/abi.h | 6 +-
arch/mips/include/asm/elf.h | 4 +
arch/mips/include/asm/mmu.h | 5 +-
arch/mips/include/asm/mmu_context.h | 2 +-
arch/mips/include/asm/processor.h | 11 +++-
arch/mips/include/asm/uasm.h | 1 +
arch/mips/include/asm/vdso.h | 29 +++++++++
arch/mips/kernel/Makefile | 2 +-
arch/mips/kernel/signal-common.h | 5 --
arch/mips/kernel/signal.c | 86 ++++++---------------------
arch/mips/kernel/signal32.c | 55 ++++-------------
arch/mips/kernel/signal_n32.c | 26 ++------
arch/mips/kernel/syscall.c | 6 ++-
arch/mips/kernel/vdso.c | 112 +++++++++++++++++++++++++++++++++++
arch/mips/mm/uasm.c | 19 +++++-
15 files changed, 226 insertions(+), 143 deletions(-)
create mode 100644 arch/mips/include/asm/vdso.h
create mode 100644 arch/mips/kernel/vdso.c





Attachment: gdb.patch
Description: Text document

<Prev in Thread] Current Thread [Next in Thread>