From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <dada1@cosmosbay.com>
Subject: Re: 2.6.21 -> 2.6.22 & 2.6.23-rc8 performance regression
Date: Mon, 01 Oct 2007 10:35:02 +0200
Message-ID: <4700B136.8050109@cosmosbay.com>
References: <200709301425.37564.nickpiggin@yahoo.com.au> <20070930223503.M8966@nuclearcat.com> <47008CB0.7010808@cosmosbay.com> <20071001.001259.28812610.davem@davemloft.net> <20071001080339.M21850@nuclearcat.com> <4700ADB7.7050102@cosmosbay.com>
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Cc: Denys <nuclearcat@nuclearcat.com>,
	David Miller <davem@davemloft.net>,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org
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Eric Dumazet a =C3=A9crit :
> Denys a =C3=A9crit :
>> Well, i can play a bit more on "live" servers. I have now hot-swap=20
>> server with
>> full gentoo,  where i can rebuild any kernel you want, with any=20
>> applied patch.
>> But it looks more like not overhead, load becoming high too "spiky",=
=20
>> and it is
>> not just permantenly higher. Also it is not normal that all system=20
>> becoming
>> unresposive (for example ping 127.0.0.1 becoming 300ms for period,=20
>> when usage
>> softirq jumps to 100%).
>>
>>  =20
> Could you try a pristine 2.6.22.9 and some patch in=20
> secure_tcp_sequence_number() like :
>
> --- drivers/char/random.c.orig 2007-10-01 10:18:42.000000000 +0200
> +++ drivers/char/random.c 2007-10-01 10:19:58.000000000 +0200
> @@ -1554,7 +1554,7 @@
> * That's funny, Linux has one built in! Use it!
> * (Networks are faster now - should this be increased?)
> */
> - seq +=3D ktime_get_real().tv64;
> + seq +=3D ktime_get_real().tv64 / 1000;
> #if 0
> printk("init_seq(%lx, %lx, %d, %d) =3D %d\n",
> saddr, daddr, sport, dport, seq);
On 32 bits machine, replace the divide by a shift  to avoid a linker=20
error (undefined reference to `__divdi3'): =20

seq +=3D ktime_get_real().tv64 >> 10;