<div dir="ltr"><div>I'm not sure how much nice level matters compared to scheduler priority. I ran a series of tests to find out what Priority and Nice level are reported by the 'top' utility.<br><br>I ran the first 6 tests by using systemd to start FreeSWITCH, 3 times as user root with each of the FS priority flags, then 3 times as user freeswitch with each of the FS flags. Then I repeated that block of tests from the command line, 3 flags as root, 3 flags as freeswitch. You won't believe what happened next!<br><br>systemd starting FreeSWITCH as 'RUNAS' user with 'FLAG' command line priority flags to FS results in top showing priority 'PRI', nice level 'NICE' on a month-old install of Debian 8 on a bare metal Dell R320 server.<br><br>RUNAS FLAG PRI NICE<br>root -rp -2 -10<br>root -np 39 19<br>root -lp 39 19<br><br>fs -rp -2 19<br>fs -np 39 19<br>fs -lp 39 19<br><br>Run as root from command line<br>root -rp -2 -10<br>root -np 20 0<br>root -lp 39 19<br><br>Run as su=freeswitch from command line<br>fs -rp 20 0<br>fs -np 20 0<br>fs -lp 39 19<br><br></div><div>Most processes show Priority of 20 so I assume that is considered "normal".<br><br></div><div>So it looks like the only way to get truly higher priority for a process is to run it as root, which I expected. Once the scheduler priority is at -2 (higher priority) I don't know whether the nice level even matters.<br><br></div><div>For now, the systemd unit file that I posted on Confluence runs as the freeswitch user so even with the -rp flag to FreeSWITCH it gets niced down to 19 which is the lowest level available for nice. Does this matter?<br><br></div><div>Is there a serious security concern running FreeSWITCH as root?<br><br></div><div>Thanks.<br><br></div>Bote<br><br></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Sep 4, 2015 at 3:38 PM, Bote Man <span dir="ltr"><<a href="mailto:bote_radio@botecomm.com" target="_blank">bote_radio@botecomm.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div><div><div><div><div>Thanks for that. I was under the impression that systemd was throwing FreeSWITCH into the generic scheduling group and starving it of resources as a result, but when I manually ran ./freeswitch as root it still showed the same values.<br><br></div>Running FS manually with -np yielded pri=20 nice=0 and System Monitor reports priority "normal"<br><br></div>Running FS manually with -rp yielded pri=-2 nice=-10 and System Monitor reports priority "very high", same results as when FS was started without any priority switch on the command line.<br><br></div>BUT! When I start FS with systemd it maintains priority=-2 but nice all the way down to 19 which is why System Monitor reports "very low". This happens even with the -rp switch specified in the unit file.<br><br></div>I don't know how scheduling priority and nice level interact on Debian, but it looks like I have a new research project for this weekend, assuming this is truly something to be concerned about. Or is it?<br><br></div>Thanks for the tips. I will report my findings to the list if I discover anything substantive.<br><br></div>Bote<br><div><div><div><div><br><br><br><br></div></div></div></div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="h5">On Fri, Sep 4, 2015 at 2:02 PM, Shaun Stokes <span dir="ltr"><<a href="mailto:shaun.stokes@itec-support.co.uk" target="_blank">shaun.stokes@itec-support.co.uk</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5">
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<div style="direction:ltr;font-family:Tahoma;color:#000000;font-size:10pt">Hi Bote,
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<div>I believe priority works in a similar way to metric (i.e. lower comes first), so <span style="font-size:10pt">-20 (most favorable scheduling) to +19 (least favorable scheduling).</span></div>
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<pre style="font-family:monospace,Courier;padding:1em;border:1px dashed rgb(47,111,171);line-height:1.3em;font-size:12.8000001907349px;background-color:rgb(249,249,249)">-rp -- enable high(realtime) priority settings
-lp -- enable low priority settings
-np -- enable normal priority settings (system default)</pre>
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<div>Source: <a href="https://wiki.freeswitch.org/wiki/Command_line" style="font-size:10pt" target="_blank">https://wiki.freeswitch.org/wiki/Command_line</a></div>
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<div>Hope this helps.</div>
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<div>Thanks,</div>
<div>Shaun<br>
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<div style="direction:ltr"><font face="Tahoma" color="#000000" size="2"><b>From:</b> <a href="mailto:freeswitch-users-bounces@lists.freeswitch.org" target="_blank">freeswitch-users-bounces@lists.freeswitch.org</a> [<a href="mailto:freeswitch-users-bounces@lists.freeswitch.org" target="_blank">freeswitch-users-bounces@lists.freeswitch.org</a>] on behalf of Bote Man [<a href="mailto:bote_radio@botecomm.com" target="_blank">bote_radio@botecomm.com</a>]<br>
<b>Sent:</b> 04 September 2015 15:54<br>
<b>To:</b> FreeSWITCH Users Help<br>
<b>Subject:</b> [Freeswitch-users] FS priority<br>
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<p class="MsoNormal">I’m trying to set the priority on a new FreeSWITCH installation built from master on Debian 8 running on bare metal. It is currently running at “very low” priority according to Resource Monitor in the GUI and ‘top’ reports FS is running
at priority = -2 (that’s negative two) and nice = 19</p>
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<p class="MsoNormal">So with the way FreeSWITCH is now launched by systemd is it considered a service or a user application that is simply run in the background?
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<p class="MsoNormal">This affects how systemd treats its control groups and priority and how I will go about troubleshooting this.</p>
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Thanks.</p>
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<p class="MsoNormal">Bote</p>
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