linux-kernel - Re: [RFC][PATCH 0/6] more detailed per-process transparent hugepage statistics

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:	Tue, 08 Feb 2011 09:54:34 -0800
From:	Dave Hansen <dave@...ux.vnet.ibm.com>
To:	Andrea Arcangeli <aarcange@...hat.com>
Cc:	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	Michael J Wolf <mjwolf@...ibm.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [RFC][PATCH 0/6] more detailed per-process transparent
 hugepage statistics

On Wed, 2011-02-02 at 01:07 +0100, Andrea Arcangeli wrote:
> > I guess we could also try and figure out whether the khugepaged CPU
> > overhead really comes from the scanning or the collapsing operations
> > themselves.  Should be as easy as some oprofiling.
> 
> Actually I already know, the scanning is super fast. So it's no real
> big deal to increase the scanning. It's big deal only if there are
> plenty more of collapse/split. Compared to the KSM scan, the
> khugepaged scan costs nothing.

Just FYI, I did some profiling on a workload that constantly split and
joined pages.  Very little of the overhead was in the scanning itself,
so I think you're dead-on here.

-- Dave

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/