Re: Utilities for EPICS on Multi-Core Linux

["Shen, Guobao" <shengb@bnl.gov>]

Hi Ralph,

On 12/11/12 5:27 PM, Ralph Lange wrote:
> Hi Guobao,
>
> As the subject, the mail body, and the documentation say:     This is
> for *LINUX*.
It is my fault. I pretend to treat mac as a linux machine, but it really is not. :)
> For the time being, the module only uses Posix calls, and might be
> working on other Posix compliant platforms. This is not by specification
> but by chance, though, and there are no plans to support anything other
> than Linux. Thus the Makefile only creates the Library for Linux platforms.
OK, now I tried it on my desktop, which is a debian linux (wheezy).
Here is the compiling error:

/usr/bin/gcc  -D_POSIX_C_SOURCE=199506L -D_POSIX_THREADS -D_XOPEN_SOURCE=500           -D_X86_  -DUNIX  -D_BSD_SOURCE -Dlinux  -D_REENTRANT   -O3 -g   -Wall    -D_GNU_SOURCE -DVERSION=\"1.1.1\" 
-mtune=generic     -m32 -fPIC -I. -I../O.Common -I. -I. -I.. -I../../include/compiler/gcc -I../../include/os/Linux -I../../include -I/home/user/epics/base-3.15.0.1/include/compiler/gcc 
-I/home/user/epics/base-3.15.0.1/include/os/Linux -I/home/user/epics/base-3.15.0.1/include       -c ../threadRules.c
../threadRules.c: In function 'modifyRTProperties':
../threadRules.c:217:60: error: 'struct epicsThreadOSD' has no member named 'schedPolicy'
../threadRules.c:222:15: error: 'struct epicsThreadOSD' has no member named 'schedPolicy'
../threadRules.c:223:63: error: 'struct epicsThreadOSD' has no member named 'schedPolicy'
../threadRules.c:227:19: error: 'struct epicsThreadOSD' has no member named 'isRealTimeScheduled'
../threadRules.c:229:19: error: 'struct epicsThreadOSD' has no member named 'isRealTimeScheduled'
../threadRules.c:248:51: error: 'struct epicsThreadOSD' has no member named 'schedPolicy'
make[2]: *** [threadRules.o] Error 1
make[2]: Leaving directory `/home/user/epics/mcoreutils/MCoreUtilsApp/O.linux-x86'
make[1]: *** [install.linux-x86] Error 2
make[1]: Leaving directory `/home/user/epics/mcoreutils/MCoreUtilsApp'
make: *** [MCoreUtilsApp.install] Error 2

$ gcc --version
gcc (Debian 4.7.2-4) 4.7.2
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Guobao
> Or do you refer to running Linux on Apple hardware?!
>
> Cheers,
> ~Ralph
>
>
> On 11.12.2012 20:21, Shen, Guobao wrote:
> > Hi Ralph,
> > After a short try, there are 2 compile problems on my Mac.
> > 1. the Mac version of cp command does not support "-T" flag. Either I
> > have to change it to use GNU cp, or remove T.
> > 2. It compiles and install documentation only. No library is produced
> > by default.
> >
> > Guobao
> >
> >
> > On 12/10/12 4:21 AM, Ralph Lange wrote:
> > > Hi Jack,
> > >
> > > On 09.12.2012 15:59, Jack Smith wrote:
> > > > > On Fri, Nov 23, 2012 at 2:48 PM, Ralph Lange <Ralph.Lange@gmx.de>
> > > > > wrote:
> > > > > MCoreUtils - Utilities for EPICS on Multi-Core Linux
> > > > >
> > > > > I recently started working on a collection of useful stuff for
> > > > > running IOCs
> > > > > on multi-core (RT or not) Linux architectures. (*)
> > > > >
> > > > > The first two modules are now available on SourceForge [1]:
> > > > >
> > > > > Real-time threadShow routines
> > > > > Enhanced threadShow functions that print LWP ID, scheduling policy,
> > > > > and CPU
> > > > > affinity.
> > > > >
> > > > > Rule-based setting of real-time properties
> > > > > Pattern matching engine that allows to set real-time properties of
> > > > > EPICS
> > > > > threads (scheduling policy, priority, and CPU affinity) by regular
> > > > > expression matching on thread names. Rules can be set in a config
> > > > > file or
> > > > > from the iocShell, and will be applied to any thread started
> > > > > through the
> > > > > libCom/OSI API of EPICS Base. This allows to restrict the complete
> > > > > IOC onto
> > > > > a subset of CPUs, dedicate CPUs to specific (driver) threads,
> > > > > fine-tune
> > > > > policies and priorities, etc.
> > > > >
> > > > > MCoreUtils need EPICS Base 3.15.0.1 or later, on a Linux platform.
> > > > >
> > > > > This project is in an early stage.
> > > > > I know that more and more EPICS sites are using this family of
> > > > > platforms and
> > > > > have to cope with similar things, so I would like to invite
> > > > > everybody to
> > > > > step forward with ideas and suggestions (and code!). I hope we can
> > > > > manage to
> > > > > minimize parallel developments, and combine efforts for a better
> > > > > real-time
> > > > > behaviour and performance of EPICS.
> > > > >
> > > > > Cheers,
> > > > > ~Ralph
> > > > I guess the purpose of MCoreUtils is to make Linux system (RT or not)
> > > > more deterministic. Right?
> > > Correct.
> > > ITER's fast controllers run a RT-Linux (RHEL-based MRG-R), but the
> > > general direction is a) to get more over-all deterministic behavior, and
> > > b) to allow to run specific RT applications on dedicated cores, i.e.
> > > restrict the IOC to a subset of the available cores.
> > >
> > > > For EPICS base 3.14.x, how do the IOCs' threads use the CPU resources
> > > > on a multi-core Linux system? Do the threads just randomly pick up any
> > > > available CPU resource?
> > > Basically, yes.
> > > The default for EPICS Base is to not use Posix real-time scheduling, so
> > > all EPICS IOC threads are using the Linux default scheduler, which will
> > > distribute them onto available CPU resources according to its
> > > implemented strategy. Which of course - strictly speaking - is not
> > > randomly, but looks a lot like it... ;-)
> > >
> > > There's a good page on the EPICS Wiki by Till Straumann [1], describing
> > > how to switch an IOC to use Posix real-time scheduling under Linux.
> > >
> > > Cheers,
> > > ~Ralph
> > >
> > > [1]
> > > https://wiki-ext.aps.anl.gov/epics/index.php/How_To_Use_Posix_Thread_Priority_Scheduling_under_Linux
> .