linux-kernel - Re: [PATCH] page_alloc.c: inline _

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 9 Oct 2017 15:53:38 +0800
From:   Aaron Lu <aaron.lu@...el.com>
To:     Anshuman Khandual <khandual@...ux.vnet.ibm.com>
Cc:     linux-mm <linux-mm@...ck.org>, lkml <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Dave Hansen <dave.hansen@...el.com>,
        Huang Ying <ying.huang@...el.com>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Kemi Wang <kemi.wang@...el.com>
Subject: Re: [PATCH] page_alloc.c: inline __rmqueue()

On Mon, Oct 09, 2017 at 01:07:36PM +0530, Anshuman Khandual wrote:
> On 10/09/2017 11:14 AM, Aaron Lu wrote:
> > __rmqueue() is called by rmqueue_bulk() and rmqueue() under zone->lock
> > and that lock can be heavily contended with memory intensive applications.
> > 
> > Since __rmqueue() is a small function, inline it can save us some time.
> > With the will-it-scale/page_fault1/process benchmark, when using nr_cpu
> > processes to stress buddy:
> > 
> > On a 2 sockets Intel-Skylake machine:
> >       base          %change       head
> >      77342            +6.3%      82203        will-it-scale.per_process_ops
> > 
> > On a 4 sockets Intel-Skylake machine:
> >       base          %change       head
> >      75746            +4.6%      79248        will-it-scale.per_process_ops
> > 
> > This patch adds inline to __rmqueue().
> > 
> > Signed-off-by: Aaron Lu <aaron.lu@...el.com>
> 
> Ran it through kernel bench and ebizzy micro benchmarks. Results
> were comparable with and without the patch. May be these are not
> the appropriate tests for this inlining improvement. Anyways it

I think so.

The benefit only appears when the lock contention is huge enough, e.g.
perf-profile.self.cycles-pp.native_queued_spin_lock_slowpath is as high
as 80% with the workload I have used.

> does not have any performance degradation either.
> 
> Reviewed-by: Anshuman Khandual <khandual@...ux.vnet.ibm.com>
> Tested-by: Anshuman Khandual <khandual@...ux.vnet.ibm.com>

Thanks!