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  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]
Date:	Thu, 14 Aug 2014 16:25:53 -0700
From:	Tom Herbert <therbert@...gle.com>
To:	David Miller <davem@...emloft.net>
Cc:	Alexander Duyck <alexander.h.duyck@...el.com>,
	Eric Dumazet <eric.dumazet@...il.com>,
	Linux Netdev List <netdev@...r.kernel.org>
Subject: Re: Performance regression on kernels 3.10 and newer

On Thu, Aug 14, 2014 at 4:20 PM, David Miller <davem@...emloft.net> wrote:
> From: Alexander Duyck <alexander.h.duyck@...el.com>
> Date: Thu, 14 Aug 2014 16:16:36 -0700
>
>> Are you sure about each socket having it's own DST?  Everything I see
>> seems to indicate it is somehow associated with IP.
>
> Right it should be, unless you have exception entries created by path
> MTU or redirects.
>
> WRT prequeue, it does the right thing for dumb apps that block in
> receive.  But because it causes the packet to cross domains as it
> does, we can't do a lot of tricks which we normally can do, and that's
> why the refcounting on the dst is there now.
>
> Perhaps we can find a clever way to elide that refcount, who knows.

I don't know if it's the same problem, but I did post a patch back in
January that would resolve false sharing of dst->__refcnt and rt_genid
in the same cacheline. We could revisit that if it helps.

Tom

> --
> 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
--
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

Powered by blists - more mailing lists