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Message-ID: <20090714162425.GA3090@ami.dom.local>
Date: Tue, 14 Jul 2009 18:24:25 +0200
From: Jarek Poplawski <jarkao2@...il.com>
To: Paweł Staszewski <pstaszewski@...are.pl>
Cc: Eric Dumazet <dada1@...mosbay.com>,
Eric Dumazet <eric.dumazet@...il.com>,
Linux Network Development list <netdev@...r.kernel.org>
Subject: Re: weird problem
On Tue, Jul 14, 2009 at 01:26:46AM +0200, Paweł Staszewski wrote:
> Jarek Poplawski pisze:
>> On Fri, Jul 10, 2009 at 04:47:54PM +0200, Jarek Poplawski wrote:
>>
>>> On Fri, Jul 10, 2009 at 01:59:00AM +0200, Paweł Staszewski wrote:
>>>
>>>> Today i make other tests with change of
>>>> /proc/sys/net/ipv4/rt_cache_rebuild_count and kernel 2.6.30.1
>>>>
>>>> And when rt_cache_rebuild_count is set to "-1" i have always load
>>>> on x86_64 machine approx 40-50% of each cpu where network card is
>>>> binded by irq_aff
>>>>
>>>> when rt_cache_rebuild_count is set to more than "-1" i have 15 to
>>>> 20 sec of 1 to 3% cpu and after 40-50% cpu
>>>>
>>> ...
>>>
>>> Here is one more patch for testing (with caution!). It adds possibility
>>> to turn off cache disabling (so it should even more resemble 2.6.28)
>>> after setting: rt_cache_rebuild_count = 0
>>>
>>> I'd like you to try this patch:
>>> 1) together with the previous patch and "rt_cache_rebuild_count = 0"
>>> to check if there is still the difference wrt. 2.6.28; Btw., let
>>> me know which /proc/sys/net/ipv4/route/* settings do you need to
>>> change and why
>>>
>>> 2) alone (without the previous patch) and "rt_cache_rebuild_count = 0"
>>>
>>> 3) if it's possible to try 2.6.30.1 without these patches, but with
>>> default /proc/sys/net/ipv4/route/* settings, and higher
>>> rt_cache_rebuild_count, e.g. 100; I'm interested if/how long it
>>> takes to trigger higher cpu load and the warning "... rebuilds is
>>> over limit, route caching disabled"; (Btw., I wonder why you didn't
>>> mention about these or maybe also other route caching warnings?)
>>>
>>
>> Here is take 2 to respect setting "rt_cache_rebuild_count = 0" even
>> after cache rebuild counter has been increased earlier. (Btw, don't
>> forget about this setting after going back to vanilla kernel.)
>>
>>
> Applied to 2.6.30.1
> 1) With
>
> rt_cache_rebuild_count = 0
> grep . /proc/sys/net/ipv4/route/*
> /proc/sys/net/ipv4/route/error_burst:1250
> /proc/sys/net/ipv4/route/error_cost:250
> /proc/sys/net/ipv4/route/gc_elasticity:4
> /proc/sys/net/ipv4/route/gc_interval:15
> /proc/sys/net/ipv4/route/gc_min_interval:0
> /proc/sys/net/ipv4/route/gc_min_interval_ms:0
> /proc/sys/net/ipv4/route/gc_thresh:190536
> /proc/sys/net/ipv4/route/gc_timeout:15
> /proc/sys/net/ipv4/route/max_size:1524288
> /proc/sys/net/ipv4/route/min_adv_mss:256
> /proc/sys/net/ipv4/route/min_pmtu:552
> /proc/sys/net/ipv4/route/mtu_expires:600
> /proc/sys/net/ipv4/route/redirect_load:5
> /proc/sys/net/ipv4/route/redirect_number:9
> /proc/sys/net/ipv4/route/redirect_silence:5120
> /proc/sys/net/ipv4/route/secret_interval:3600
>
> I tune this route parameters after looking of traffic/route cache to have not many entries in cache that are not needed anymore
> so gc_timeout = 15
> limit of max entries = 1524288
> And make route cahce a little more "faster" for me after tune
> gc_elasticity
> secret_interval
> gc_interval
> gc_thresh
>
> So with this parameters 15 sec of something like this:
> 00:41:23 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle
> 00:41:24 all 0.00 0.00 0.12 0.00 1.49 10.46 0.00 0.00 87.92
> 00:41:24 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:41:24 1 0.00 0.00 0.00 0.00 4.00 36.00 0.00 0.00 60.00
> 00:41:24 2 0.00 0.00 0.00 0.00 8.91 47.52 0.00 0.00 43.56
> 00:41:24 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:41:24 4 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:41:24 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:41:24 6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:41:24 7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
>
> and 15 sec of something like this:
> 00:41:44 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle
> 00:41:45 all 0.00 0.00 0.00 0.00 0.00 0.42 0.00 0.00 99.58
> 00:41:45 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:41:45 1 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.00 99.00
> 00:41:45 2 0.00 0.00 0.00 0.00 0.00 2.04 0.00 0.00 97.96
> 00:41:45 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:41:45 4 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:41:45 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:41:45 6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:41:45 7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
>
> So i change /proc/sys/net/ipv4/route/gc_timeout to 1
> with rt_cache_rebuild_count = 0
> And output is like 20 sec of something like this
> 00:48:52 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle
> 00:48:53 all 0.00 0.00 0.19 0.00 0.19 0.58 0.00 0.00 99.03
> 00:48:53 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:48:53 1 0.00 0.00 0.99 0.00 0.99 0.00 0.00 0.00 98.02
> 00:48:53 2 0.00 0.00 0.00 0.00 0.00 2.00 0.00 0.00 98.00
> 00:48:53 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:48:53 4 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:48:53 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:48:53 6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:48:53 7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
>
> and after this two second of something like this:
> 00:48:49 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle
> 00:48:50 all 0.00 0.00 0.09 0.00 0.27 2.17 0.00 0.00 97.46
> 00:48:50 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:48:50 1 0.00 0.00 0.00 0.00 1.96 6.86 0.00 0.00 91.18
> 00:48:50 2 0.00 0.00 0.00 0.00 0.99 16.83 0.00 0.00 82.18
> 00:48:50 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:48:50 4 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:48:50 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:48:50 6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:48:50 7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
>
> 00:48:50 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle
> 00:48:51 all 0.00 0.00 0.00 0.00 1.86 10.41 0.00 0.00 87.73
> 00:48:51 0 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.00 99.00
> 00:48:51 1 0.00 0.00 0.00 0.00 4.85 26.21 0.00 0.00 68.93
> 00:48:51 2 0.00 0.00 1.00 0.00 5.00 29.00 0.00 0.00 65.00
> 00:48:51 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:48:51 4 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:48:51 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:48:51 6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:48:51 7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
>
Could you remind us how it differs from 2.6.28 with the same settings?
>
> Another test:
>
> gc_timeout = 1
> rt_cache_rebuild_count = 100
> 10 to 14 sec of something like this:
> 00:51:36 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle
> 00:51:37 all 0.00 0.00 0.00 0.00 0.00 0.27 0.00 0.00 99.73
> 00:51:37 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:51:37 1 0.00 0.00 0.00 0.00 0.00 2.00 0.00 0.00 98.00
> 00:51:37 2 0.00 0.00 0.00 0.00 0.00 1.00 0.00 0.00 99.00
> 00:51:37 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:51:37 4 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:51:37 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:51:37 6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:51:37 7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
>
> and two seconds of 10 to 30% cpu load more
>
>
> 2).
> Only last patch and almost all the time output like this
> 00:59:49 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle
> 00:59:50 all 0.00 0.00 0.13 0.00 1.73 8.00 0.00 0.00 90.13
> 00:59:50 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:59:50 1 0.00 0.00 0.00 0.00 4.00 24.00 0.00 0.00 72.00
> 00:59:50 2 0.00 0.00 0.00 0.00 8.91 34.65 0.00 0.00 56.44
> 00:59:50 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:59:50 4 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:59:50 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:59:50 6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 00:59:50 7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
>
> sometimes after 15 to 30 sec i have 1 to 2% cpu load
And how long do you have this 1 to 2% load? Is it with:
rt_cache_rebuild_count = 0
gc_timeout = 1?
Maybe you could describe the main difference with or without the first
patch?
>
> 3).
>
> with default settings and without this patch i have almost all the time output like this:
You mean without these two patches, right? So, there is no breaks with
less load like above?
> 01:21:40 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle
> 01:21:41 all 0.00 0.00 0.00 0.00 2.14 10.97 0.00 0.00 86.89
> 01:21:41 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 01:21:41 1 0.00 0.00 0.00 0.00 6.93 34.65 0.00 0.00 58.42
> 01:21:41 2 0.00 0.00 0.00 0.00 7.07 42.42 0.00 0.00 50.51
> 01:21:41 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 01:21:41 4 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 01:21:41 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 01:21:41 6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 01:21:41 7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
>
>
>
> with my settings:
> /proc/sys/net/ipv4/route/error_burst:1250
> /proc/sys/net/ipv4/route/error_cost:250
> /proc/sys/net/ipv4/route/gc_elasticity:4
> /proc/sys/net/ipv4/route/gc_interval:15
> /proc/sys/net/ipv4/route/gc_min_interval:0
> /proc/sys/net/ipv4/route/gc_min_interval_ms:0
> /proc/sys/net/ipv4/route/gc_thresh:190536
> /proc/sys/net/ipv4/route/gc_timeout:15
> /proc/sys/net/ipv4/route/max_size:1524288
> /proc/sys/net/ipv4/route/min_adv_mss:256
> /proc/sys/net/ipv4/route/min_pmtu:552
> /proc/sys/net/ipv4/route/mtu_expires:600
> /proc/sys/net/ipv4/route/redirect_load:5
> /proc/sys/net/ipv4/route/redirect_number:9
> /proc/sys/net/ipv4/route/redirect_silence:5120
> /proc/sys/net/ipv4/route/secret_interval:3600
>
>
> 15 sec of 30 to 50 % cpu and 15 sec 1 to 2 % cpu
>
> with /proc/sys/net/ipv4/route/gc_interval:1
> almost all the time like this
> 01:23:45 CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle
> 01:23:46 all 0.00 0.00 0.00 0.00 0.00 0.12 0.00 0.00 99.88
> 01:23:46 0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 01:23:46 1 0.00 0.00 0.00 0.00 1.00 0.00 0.00 0.00 99.00
> 01:23:46 2 0.00 0.00 0.00 0.00 0.00 1.02 0.00 0.00 98.98
> 01:23:46 3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 01:23:46 4 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 01:23:46 5 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 01:23:46 6 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
> 01:23:46 7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100.00
>
> with max two outputs of 20 to 30% cpu in different times from 12 to 15sec
Didn't you see any: "... rebuilds is over limit, route caching
disabled" warning?
>
>
> And i dont know but i think patch for turning off route cache is not
> working because with this patches and rt_cache_rebuild_count = 0
If you mean the patch #2, it does something opposite: with
rt_cache_rebuild_count = 0 it turns off automatic "cache disabling"
after rt_cache_rebuild_count events signaled with the above-mentionned
warning, which was introduced in 2.6.29. Sorry for not describing this
enough.
Thanks,
Jarek P.
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