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From Yongming Zhao <ming....@gmail.com>
Subject Re: Ramdisk - 6.2.1 vs 7.0.0
Date Sat, 17 Jun 2017 10:23:35 GMT
good job, log collation host down should only switch to orphan logging instead, that memory
leak is not as expected, please continue your investigation and file the issue in the github
with some details.

patch welcome, as always

- Yongming Zhao 赵永明

> 在 2017年6月17日,上午2:13,Chou, Peter <pbchou@labs.att.com> 写道:
> 
> Bryan,
>  
> Turns out that this memory leak is the result of configuring a log collation host in
“logs_xml.config” and then having the host be down during the traffic run. We verified
that this occurs with vanilla 6.2.1. We also noticed that there was a memory leak fix in this
function patched in TS-4872, which is present in 6.2.x, 7.1.x, and master. So we tried the
latest 6.2.x (current) from yesterday, but the memory leak still occurred. We have also seen
that bringing up the log host during the test run stabilizes the memory allocation so we’re
pretty sure that this is the trigger for the memory leak.
>  
> Some heap-check output from ATS compiled with tcmalloc --
> Total: 3014.2 MB
>   2902.3  96.3%  96.3%   2902.3  96.3% ats_malloc
>     76.0   2.5%  98.8%     76.0   2.5% ats_memalign
>     35.8   1.2% 100.0%   2938.1  97.5% LogObject::_checkout_write
>      0.1   0.0% 100.0%      0.1   0.0% BaseLogFile::open_file
>      0.0   0.0% 100.0%      0.0   0.0% ResourceTracker::lookup (inline)
>  
> Thanks,
> Peter
>  
>  
> From: Bryan Call [mailto:bcall@apache.org] 
> Sent: Saturday, June 10, 2017 8:12 AM
> To: users@trafficserver.apache.org
> Subject: Re: Ramdisk - 6.2.1 vs 7.0.0
>  
> Do you have TLS connections? (https).  You can use tcmalloc or jemalloc to profile the
memory allocation.
>  
> -Bryan
>  
> On Jun 9, 2017, at 11:50 AM, Chou, Peter <pbchou@labs.att.com <mailto:pbchou@labs.att.com>>
wrote:
>  
> Bryan,
>  
> Our default_inactivity_timeout is set to 300s. We have looked at the memory dump in traffic.out
as well, but we’re stumped because the memory that is tracked in the dump only comes out
to about 8GB and 6GB total allocated and used respectively while pmap -x <pid> reports
around 26GB memory allocated to the process.
>  
> From pmap -- 26127468 11646528 11646094    8773892  11644512 12341772 == [ size rss pss
referenced anonymous swap ] (KB)
> From traffic.out -- 7895071920 |         5956998576 |            | TOTAL (B)
>  
> Is this similar to run-away anon region allocation seen before? Appreciate any insights.
>  
> Thanks,
> Peter
>  
>  
> From: Bryan Call [mailto:bcall@apache.org <mailto:bcall@apache.org>] 
> Sent: Friday, June 09, 2017 9:02 AM
> To: users@trafficserver.apache.org <mailto:users@trafficserver.apache.org>
> Subject: Re: Ramdisk - 6.2.1 vs 7.0.0
>  
> What is your proxy.config.net.default_inactivity_timeout set to?  You can also do a dump
of the memory by doing:
>  
> $ sudo kill -SIGUSR1 $(pidof traffic_server). # and look at traffic.out.
>  
> That will give a pretty good idea on where the memory is being used.
>  
> -Bryan
>  
> On Jun 8, 2017, at 3:35 PM, Jeremy Payne <jp557198@gmail.com <mailto:jp557198@gmail.com>>
wrote:
>  
> ATS versions - 6.2.1
> Cache disk - 18G ramdisk - /dev/ram0
> Storage.config configured to use 14G of ramdisk
> System memory - 32G
> Traffic type - HLS Live
> Connections - sustained 4k
> Trafffic - 5-6gbps
> Hit ratio - 97%
>  
> So it looks like I misread/misinterpreted a few things during testing referenced in my
previous email.
> It looks like my issue was never run away memory using ramdisk,
> it looks like something internal to ATS that I can't seem to isolate.
>  
> Since I am not seeing this type of memory consumption with my large-file/VOD cache servers,
> and the connection profile is much different, I am guessing what may be at issue is the
long living 
> connections. ATS active timeout is currently set to 3600. This is live traffic so connections
stay open for a hour
> and then closed.  Where as with my large-file/VOD cache servers, connections only remain
> open for as long as a file/title is being retrieved. 10-15mins max.
>  
> Has anyone seen any issues with this type of connection profile and ATS 6.2.1? 
>  
> This doesnt seem to be an issue with 7.0, so not sure what may have changed between releases.
>  
> Thanks!
>  
>   
>  
> On Tue, Jun 6, 2017 at 8:32 AM, Jeremy Payne <jp557198@gmail.com <mailto:jp557198@gmail.com>>
wrote:
> ATS versions - 6.2.1 and 7.0.0
> Cache disk - 18G ramdisk - /dev/ram0
> System memory - 32G
> Traffic type - HLS Live
>  
> While testing live HLS traffic, I noticed that ATS 6.2.1. continued to use ramdisk until

> eventually traffic_server was restarted(via trafic_cop) as result of 'oom killer'
>  
> Testing with ATS 7.0.0 I saw memory use remain stable once the ramdisk reached it's 
> 'configured' capacity. 
>  
> I looked through the 7.0 changelog and didnt see anything obvious, so maybe someone is
aware of an undocumented change which impacts ATS 'honoring' configured  ramdisk boundaries.
> Understood ATS may not know the difference between /dev/sdX and /dev/ramX.. But just
> putting this out to the community just in case I am missing something.
>  
> Jeremy


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