netdev - Re: [PATCH 1/3] sysfs directory scaling: rbtree for dirent name lookups

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]

Message-ID: <m1zl735k1e.fsf@fess.ebiederm.org>
Date:	Tue, 03 Nov 2009 14:18:53 -0800
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	Benjamin LaHaise <bcrl@...et.ca>
Cc:	Greg KH <greg@...ah.com>, Eric Dumazet <eric.dumazet@...il.com>,
	Octavian Purdila <opurdila@...acom.com>,
	netdev@...r.kernel.org, Cosmin Ratiu <cratiu@...acom.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] sysfs directory scaling: rbtree for dirent name lookups

Benjamin LaHaise <bcrl@...et.ca> writes:

> On Tue, Nov 03, 2009 at 01:32:33PM -0800, Eric W. Biederman wrote:
>> Are your numbers from your application and are they real world?
>> In which case they are interesting, but it would be good if
>> we could also have microbenchmark numbers that just measure
>> the sysfs costs.   If nothing else I am seeing a big startup
>> overhead that isn't being subtracted out that makes it hard
>> to see the real costs here.
>
> They're application based, so there's a bunch of other overhead included 
> that won't show up on a microbenchmark.  Each interface requires a round 
> trip between 2 L2TP daemons, so there are lots of syscalls and other cache 
> polluting effects that won't show up on a microbenchmark.  One of the L2TP 
> daemons is configured not to instantiate any kernel state -- running in 
> this mode, it has very little overhead.
>
> The other thing to note is that the costs posted are how long it takes to 
> add an additional 5,000 interfaces in the given range, not the total time 
> to add say 35,000 interfaces (I didn't feel like waiting that long).

Ok.  That makes a lot more sense.  The times you posted ideally would be flat
but they go up from 12s to 60s.

Eric
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html