From: cold cold <nedkonedev@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: netdev@vger.kernel.org
Subject: Re: 0% cpu usasge after fresh boot or net restart but 10% CPU if kernel flush route cache
Date: Thu, 28 Jan 2010 20:49:28 +0200 [thread overview]
Message-ID: <41ac0f9e1001281049g119d5b1bgbc47f78150cac6ee@mail.gmail.com> (raw)
In-Reply-To: <1264698380.2930.20.camel@edumazet-laptop>
On Thu, Jan 28, 2010 at 7:06 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> Le jeudi 28 janvier 2010 à 18:26 +0200, cold cold a écrit :
>> On Thu, Jan 28, 2010 at 6:09 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
>> > Le jeudi 28 janvier 2010 à 11:14 +0200, cold cold a écrit :
>> >
>> >>
>> >> RX Kpps : 57 TX Kpps : 53 RX Kbits : 331184 TX Kbits : 306213
>> >> RX Kpps : 59 TX Kpps : 54 RX Kbits : 345517 TX Kbits : 304323
>> >> RX Kpps : 56 TX Kpps : 52 RX Kbits : 331418 TX Kbits : 296032
>> >> RX Kpps : 60 TX Kpps : 54 RX Kbits : 362007 TX Kbits : 297371
>> >> RX Kpps : 59 TX Kpps : 52 RX Kbits : 360455 TX Kbits : 280603
>> >>
>> >>
>> >> ON one cpu, gc_interval to 1, gc_elasticity 2
>> >>
>> >> Cpu0 : 0.0%us, 0.0%sy, 0.0%ni, 72.0%id, 0.0%wa, 8.3%hi, 19.7%si, 0.0%st
>> >> Cpu1 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
>> >> Cpu2 : 0.0%us, 0.3%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
>> >> Cpu3 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
>> >>
>> >> ------------------------------------------------------------------------------
>> >> PerfTop: 17064 irqs/sec kernel:98.0% [100000 cycles], (all, 4 CPUs)
>> >> ------------------------------------------------------------------------------
>> >>
>> >> samples pcnt kernel function
>> >> _______ _____ _______________
>> >>
>> >> 40388.00 - 27.8% : acpi_idle_do_entry
>> >> 24651.00 - 17.0% : read_hpet
>> >> 4271.00 - 2.9% : _spin_lock
>> >> 3388.00 - 2.3% : pskb_expand_head
>> >> 3288.00 - 2.3% : igb_poll [igb]
>> >> 3246.00 - 2.2% : irq_entries_start
>> >> 2868.00 - 2.0% : dev_gro_receive
>> >> 2665.00 - 1.8% : igb_xmit_frame_adv [igb]
>> >> 2513.00 - 1.7% : ip_route_input
>> >> 2144.00 - 1.5% : igb_clean_tx_irq [igb]
>> >> 1842.00 - 1.3% : __slab_free
>> >> 1544.00 - 1.1% : dev_queue_xmit
>> >> 1423.00 - 1.0% : igb_msix_rx [igb]
>> >> 1353.00 - 0.9% : __alloc_skb
>> >> 1285.00 - 0.9% : eth_type_trans
>> >> --
>> >
>> > All this seems pretty normal profile (regarding networking functions),
>> > your machine should scale without problem.
>> >
>> > Of course, the two first functions (acpi_idle_do_entry() & read_hpet())
>> > look suspicious but I have no idea why.
>> >
>>
>> i make with flushing without gc on 2 cpu 2 time more traffic and CPU
>> usage about 5 times less
>>
>> top - 11:22:04 up 6:45, 5 users, load average: 0.00, 0.10, 0.25
>> Tasks: 84 total, 1 running, 83 sleeping, 0 stopped, 0 zombie
>> Cpu0 : 0.0%us, 0.3%sy, 0.0%ni, 94.0%id, 0.0%wa, 1.7%hi, 4.0%si, 0.0%st
>> Cpu1 : 0.3%us, 0.0%sy, 0.0%ni, 97.7%id, 0.0%wa, 0.7%hi, 1.3%si, 0.0%st
>> Cpu2 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
>> Cpu3 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
>>
>
> pure luck I guess, since you use two cpus here instead of one, but
> nothing guarantee this.
>
>>
>> RX Kpps : 90 TX Kpps : 75 RX Kbits : 582791 TX Kbits : 413873
>> RX Kpps : 87 TX Kpps : 74 RX Kbits : 546327 TX Kbits : 415852
>> RX Kpps : 87 TX Kpps : 74 RX Kbits : 544820 TX Kbits : 418339
>> RX Kpps : 88 TX Kpps : 73 RX Kbits : 569143 TX Kbits : 406438
>> --
>
> Not sure I understand your goals. Previous numbers were with less
> trafic ?
>
> What do you want ? your cpus being idle, or your router being able to
> forward packets without drops ?
>
> Good, but if you drop packets when real garbage collection is done, you
> loose. Make your choice :)
>
>
what you mean drop packets ?
i test 2 different things and shearing results with you
first test with high CPU is with garbage collection function
second results represent CPU usage with totally disabled garbage collection
next prev parent reply other threads:[~2010-01-28 18:56 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-26 16:58 0% cpu usasge after fresh boot or net restart but 10% CPU if kernel flush route cache cold cold
2010-01-27 15:26 ` Eric Dumazet
2010-01-27 19:53 ` cold cold
2010-01-27 21:18 ` Eric Dumazet
2010-01-28 9:14 ` cold cold
2010-01-28 16:09 ` Eric Dumazet
2010-01-28 16:26 ` cold cold
2010-01-28 17:06 ` Eric Dumazet
2010-01-28 18:49 ` cold cold [this message]
2010-01-28 21:16 ` Eric Dumazet
2010-01-29 7:38 ` cold cold
2010-01-29 9:06 ` Eric Dumazet
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