From: Joe Perches <joe@perches.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ben Hutchings <bhutchings@solarflare.com>,
David Miller <davem@davemloft.net>,
Andrew Morton <akpm@linux-foundation.org>,
netdev <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Tom Herbert <therbert@google.com>
Subject: Re: [PATCH v2 net-next] softirq: reduce latencies
Date: Fri, 04 Jan 2013 00:15:51 -0800 [thread overview]
Message-ID: <1357287351.5452.44.camel@joe-AO722> (raw)
In-Reply-To: <1357285780.21409.28416.camel@edumazet-glaptop>
On Thu, 2013-01-03 at 23:49 -0800, Eric Dumazet wrote:
> In various network workloads, __do_softirq() latencies can be up
> to 20 ms if HZ=1000, and 200 ms if HZ=100.
> This patch changes the fallback to ksoftirqd condition to :
> - A time limit of 2 ms.
[]
> diff --git a/kernel/softirq.c b/kernel/softirq.c
[]
> +#define MAX_SOFTIRQ_TIME max(1, (2*HZ/1000))
And if HZ is 10000?
> asmlinkage void __do_softirq(void)
> {
[]
> + unsigned long end = jiffies + MAX_SOFTIRQ_TIME;
Perhaps MAX_SOFTIRQ_TIME should be
#define MAX_SOFTIRQ_TIME msecs_to_jiffies(2)
though it would be nicer if it were a compile time constant.
next prev parent reply other threads:[~2013-01-04 8:15 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-03 12:28 [PATCH net-next] softirq: reduce latencies Eric Dumazet
2013-01-03 20:46 ` Andrew Morton
2013-01-03 22:41 ` Eric Dumazet
2013-01-04 5:16 ` Namhyung Kim
2013-01-04 6:53 ` Eric Dumazet
[not found] ` <787701357283699@web24e.yandex.ru>
2013-01-04 7:46 ` Eric Dumazet
2013-01-03 22:08 ` Ben Hutchings
2013-01-03 22:40 ` Eric Dumazet
2013-01-04 7:49 ` [PATCH v2 " Eric Dumazet
2013-01-04 8:15 ` Joe Perches [this message]
2013-01-04 8:23 ` Eric Dumazet
2013-01-04 9:12 ` Joe Perches
2013-01-04 17:00 ` Eric Dumazet
2013-01-04 21:15 ` [PATCH] jiffies conversions: Use compile time constants when possible Joe Perches
2013-01-04 21:49 ` [PATCH v2 net-next] softirq: reduce latencies David Miller
-- strict thread matches above, loose matches on Subject: below --
2013-01-05 8:58 Sedat Dilek
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