linux-kernel - Re: devpts mounts too slowly

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 for Android: free password hash cracker in your pocket

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

Message-ID: <4A526AEF.3070407@zytor.com>
Date:	Mon, 06 Jul 2009 14:21:51 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Alexey Vlasov <renton@...ton.name>
CC:	Ray Lee <ray-lk@...rabbit.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: devpts mounts too slowly

Alexey Vlasov wrote:
> On Tue, Jun 09, 2009 at 05:02:59PM -0700, H. Peter Anvin wrote:
> 
>> A quick script seems to confirm that the time starts creeping up as the
>> number of mount points increase; on my Core i7 system the 10000th mount
>> takes around 50 ms whereas the early instances are submillisecond, and
>> the increase *seems* to be O(n log n) or thereabouts -- slightly
>> superlinear but not a good fit for a power law.
> 
> I have prepared a new machine for testing, and I don't see any slowdown
> by mounting devpts.
> Total mounts on it:
> # wc -l /proc/mounts
> 153481 /proc/mounts
> # fgrep -c devpts /proc/mounts
> 10231
> 
> On my other servers there're slowdown already by this number of:
> # wc -l /proc/mounts
> 49889 /proc/mounts
> # fgrep -c devpts /proc/mounts
> 3323
> 
> But the first box is totally empty, others are in use, may be this
> matters?
> 

Do you have /selinux mounted on one of them?

	-hpa

--
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/