From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Byungchul Park <byungchul.park@lge.com>
Cc: peterz@infradead.org, mingo@kernel.org, tglx@linutronix.de,
walken@google.com, boqun.feng@gmail.com, kirill@shutemov.name,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
iamjoonsoo.kim@lge.com, akpm@linux-foundation.org,
npiggin@gmail.com
Subject: Re: [PATCH v3 01/15] x86/dumpstack: Optimize save_stack_trace
Date: Tue, 13 Sep 2016 08:18:02 -0500 [thread overview]
Message-ID: <20160913131802.oiwxgpmccn7uufef@treble> (raw)
In-Reply-To: <1473759914-17003-2-git-send-email-byungchul.park@lge.com>
On Tue, Sep 13, 2016 at 06:45:00PM +0900, Byungchul Park wrote:
> Currently, x86 implementation of save_stack_trace() is walking all stack
> region word by word regardless of what the trace->max_entries is.
> However, it's unnecessary to walk after already fulfilling caller's
> requirement, say, if trace->nr_entries >= trace->max_entries is true.
>
> I measured its overhead and printed its difference of sched_clock() with
> my QEMU x86 machine. The latency was improved over 70% when
> trace->max_entries = 5.
This code will (probably) be obsoleted soon with my new unwinder.
Also, my previous comment was ignored:
Instead of adding a new callback, why not just check the ops->address()
return value? It already returns an error if the array is full.
I think that would be cleaner and would help prevent more callback
sprawl.
--
Josh
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-09-13 13:18 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-13 9:44 [PATCH v3 00/15] lockdep: Implement crossrelease feature Byungchul Park
2016-09-13 9:45 ` [PATCH v3 01/15] x86/dumpstack: Optimize save_stack_trace Byungchul Park
2016-09-13 13:18 ` Josh Poimboeuf [this message]
2016-09-13 14:54 ` Byungchul Park
2016-09-13 9:45 ` [PATCH v3 02/15] x86/dumpstack: Add save_stack_trace()_fast() Byungchul Park
2016-09-13 13:20 ` Josh Poimboeuf
2016-09-13 9:45 ` [PATCH v3 03/15] lockdep: Refactor lookup_chain_cache() Byungchul Park
2016-09-15 15:33 ` Nilay Vaish
2016-09-19 3:05 ` Byungchul Park
2016-09-19 16:36 ` Nilay Vaish
2016-09-20 2:00 ` Byungchul Park
2016-09-13 9:45 ` [PATCH v3 04/15] lockdep: Add a function building a chain between two classes Byungchul Park
2016-09-13 9:45 ` [PATCH v3 05/15] lockdep: Make check_prev_add can use a separate stack_trace Byungchul Park
2016-09-13 9:45 ` [PATCH v3 06/15] lockdep: Make save_trace can skip stack tracing of the current Byungchul Park
2016-09-13 9:45 ` [PATCH v3 07/15] lockdep: Implement crossrelease feature Byungchul Park
2016-09-13 10:05 ` Peter Zijlstra
2016-09-13 12:09 ` Peter Zijlstra
2016-09-13 15:14 ` Byungchul Park
2016-09-13 15:05 ` Peter Zijlstra
2016-09-13 17:12 ` Byungchul Park
2016-09-13 19:38 ` Peter Zijlstra
2016-09-13 21:42 ` Peter Zijlstra
2016-09-14 1:01 ` Byungchul Park
2016-09-14 2:27 ` Byungchul Park
2016-09-14 4:49 ` Byungchul Park
2016-09-14 8:11 ` Peter Zijlstra
2016-09-19 2:41 ` Byungchul Park
2016-09-19 8:50 ` Peter Zijlstra
2016-09-20 5:50 ` Byungchul Park
2016-09-20 6:26 ` Byungchul Park
2016-09-21 1:37 ` Byungchul Park
2016-09-22 2:57 ` Byungchul Park
2016-09-13 9:45 ` [PATCH v3 08/15] lockdep: Make crossrelease use save_stack_trace_fast() Byungchul Park
2016-09-13 9:45 ` [PATCH v3 09/15] lockdep: Make print_circular_bug() crosslock-aware Byungchul Park
2016-09-13 9:45 ` [PATCH v3 10/15] lockdep: Apply crossrelease to completion operation Byungchul Park
2016-09-13 9:45 ` [PATCH v3 11/15] pagemap.h: Remove trailing white space Byungchul Park
2016-09-13 9:45 ` [PATCH v3 12/15] lockdep: Apply crossrelease to PG_locked lock Byungchul Park
2016-09-13 9:45 ` [PATCH v3 13/15] lockdep: Apply lock_acquire(release) on __Set(__Clear)PageLocked Byungchul Park
2016-09-13 9:45 ` [PATCH v3 14/15] lockdep: Move data used in CONFIG_LOCKDEP_PAGELOCK from page to page_ext Byungchul Park
2016-09-13 9:45 ` [PATCH v3 15/15] lockdep: Crossrelease feature documentation Byungchul Park
2016-09-15 17:25 ` Nilay Vaish
2016-09-19 2:59 ` Byungchul Park
2016-09-16 15:47 ` Nilay Vaish
2016-09-19 3:00 ` Byungchul Park
2016-09-20 5:00 ` Byungchul Park
2016-09-13 9:58 ` [FYI] Output of 'cat /proc/lockdep' after applying crossrelease Byungchul Park
2016-11-02 5:42 ` [REVISED DOC on v3] Crossrelease Lockdep Byungchul Park
2016-11-03 8:18 ` Byungchul Park
2016-11-08 2:54 ` Byungchul Park
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=20160913131802.oiwxgpmccn7uufef@treble \
--to=jpoimboe@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=boqun.feng@gmail.com \
--cc=byungchul.park@lge.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=kirill@shutemov.name \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mingo@kernel.org \
--cc=npiggin@gmail.com \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=walken@google.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 NNTP newsgroup(s).