netdev - Re: [PATCH v6] net: batch skb dequeueing from softnet input_pkt

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:	Sun, 02 May 2010 19:47:04 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Arjan van de Ven <arjan@...radead.org>
Cc:	Andi Kleen <andi@...stfloor.org>,
	David Miller <davem@...emloft.net>, hadi@...erus.ca,
	xiaosuo@...il.com, therbert@...gle.com, shemminger@...tta.com,
	netdev@...r.kernel.org, lenb@...nel.org
Subject: Re: [PATCH v6] net: batch skb dequeueing from softnet
 input_pkt_queue

Le dimanche 02 mai 2010 à 10:43 -0700, Arjan van de Ven a écrit :
> On Sun, 02 May 2010 18:35:31 +0200
> Eric Dumazet <eric.dumazet@...il.com> wrote
> > 
> > 
> > You mean we can wakeup a thread with something else than an IPI ?
> > 
> 
> actually we can.
> 
> mwait is not only "go idle", it is "go idle until someone writes to
> <THIS> cacheline". where <THIS> is set up with a "monitor" instruction.
> We don't need to send an ipi per se.. all we need is to write to the
> right cacheline that we're monitoring.
> 
> 

Thats a bit x86 specific, isnt it ?

But we want to eventually send a 'signal' to a cpu, even if not blocked
in idle, so that it can do following action :

/* Called from hardirq (IPI) context */
static void rps_trigger_softirq(void *data)
{
        struct softnet_data *sd = data;

        __napi_schedule(&sd->backlog);
        __get_cpu_var(netdev_rx_stat).received_rps++;
}

And it also should be portable ;)

If something else than an IPI is available, please let us know !

Thanks


--
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