From: Peter Zijlstra <peterz@infradead.org>
To: mingo@kernel.org, rusty@rustcorp.com.au,
mathieu.desnoyers@efficios.com, oleg@redhat.com,
paulmck@linux.vnet.ibm.com, torvalds@linux-foundation.org
Cc: linux-kernel@vger.kernel.org, andi@firstfloor.org,
rostedt@goodmis.org, tglx@linutronix.de, peterz@infradead.org
Subject: [PATCH v4 0/9] latched RB-trees and __module_address()
Date: Wed, 08 Apr 2015 18:48:13 +0200 [thread overview]
Message-ID: <20150408164813.810874878@infradead.org> (raw)
This series is aimed at making __module_address() go fast(er).
The reason for doing so is that most stack unwinders use kernel_text_address()
to validate each frame. Perf and ftrace (can) end up doing a lot of stack
traces from performance sensitive code.
On the way there it:
- annotates and sanitizes module locking
- introduces the latched RB-tree
- employs it to make __module_address() go fast.
I've build and boot tested this on x86_64 with modules and lockdep
enabled. Performance numbers (below) are done with lockdep disabled.
As previously mentioned; the reason for writing the latched RB-tree as generic
code is mostly for clarity/documentation purposes; as there are a number of
separate and non trivial bits to the complete solution.
As measued on my ivb-ep system with 84 modules loaded; prior to patching
the test module (below) reports:
avg +- stdev
Before: 1689 +- 287 [ns] per __module_address() call
After: 137 +- 38 [ns] per __module_address() call
Note; I have also tested things like: perf record -a -g modprobe
mod_test, to make 'sure' to hit some of the more interesting paths.
Changes since last time:
- depend on CONFIG_PERF_EVENTS || CONFIG_TRACING -- akpm
- use within_module() for jump_labels -- rusty
- minor comment changes -- Compudj, mingo
Rusty, please consider merging this.
next reply other threads:[~2015-04-08 17:08 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-08 16:48 Peter Zijlstra [this message]
2015-04-08 16:48 ` [PATCH v4 1/9] module: Sanitize RCU usage and locking Peter Zijlstra
2015-04-09 4:21 ` Lai Jiangshan
2015-04-09 12:36 ` Peter Zijlstra
2015-04-08 16:48 ` [PATCH v4 2/9] module: Annotate module version magic Peter Zijlstra
2015-04-08 16:48 ` [PATCH v4 3/9] module, jump_label: Fix module locking Peter Zijlstra
2015-04-08 16:48 ` [PATCH v4 4/9] rbtree: Make lockless searches non-fatal Peter Zijlstra
2015-04-08 16:48 ` [PATCH v4 5/9] seqlock: Better document raw_write_seqcount_latch() Peter Zijlstra
2015-04-08 16:48 ` [PATCH v4 6/9] rbtree: Implement generic latch_tree Peter Zijlstra
2015-04-09 8:09 ` Lai Jiangshan
2015-04-09 8:14 ` Peter Zijlstra
2015-04-09 8:55 ` Lai Jiangshan
2015-04-09 12:13 ` Peter Zijlstra
2015-04-09 12:28 ` Peter Zijlstra
2015-04-09 16:31 ` Linus Torvalds
2015-04-09 16:59 ` Peter Zijlstra
2015-04-09 17:12 ` Linus Torvalds
2015-04-09 17:17 ` Linus Torvalds
2015-04-08 16:48 ` [PATCH v4 7/9] module: Optimize __module_address() using a latched RB-tree Peter Zijlstra
2015-04-08 16:48 ` [PATCH v4 8/9] module: Make the mod_tree stuff conditional on PERF_EVENTS || TRACING Peter Zijlstra
2015-04-08 16:48 ` [PATCH v4 9/9] module: Use __module_address() for module_address_lookup() Peter Zijlstra
2015-04-08 22:08 ` [PATCH v4 0/9] latched RB-trees and __module_address() Andi Kleen
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
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20150408164813.810874878@infradead.org \
--to=peterz@infradead.org \
--cc=andi@firstfloor.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=mingo@kernel.org \
--cc=oleg@redhat.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=rostedt@goodmis.org \
--cc=rusty@rustcorp.com.au \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
/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 NNTP newsgroup(s).