bug#24516:

[Nelson H. F. Beebe]

Thanks, Jim, for the patch to backref-multibyte-slow; I've applied it
to a new directory grep-2.25.92-f3e9.p1, and have builds in progress
now on the Fedora systems.

I think that any kind of wallclock-time-dependent test in a package
test suite is seriously prone to failure.  Although some developers
may have the luxury of a fast personal machine on which nothing else
is running when a package is built, many of us live in multiuser
environments where the load on the build machines is completely
unpredictable, and beyond our control.

Also, for someone like me with numerous VMs running on a single
desktop, parallel builds will certainly drive up the load.  With the
large number of test systems that I have, there is no reasonable way
to do the builds sequentially, because such a process could take hours
to days to complete.

My desktop has 16 cores (as far as Linux and the top utility are
concerned: it has a hyperthreaded 8-core 3GHz Xeon E5-1660v3 with 64GB
DDR-4 RAM).  Even during builds, it is rare for more than half the
cores to be more than 75% busy.  Here is a snapshot from top taken
during the Fedora grep builds:

    top - 07:46:43 up 71 days, 17:23,  7 users,  load average: 18.57, 18.60, 
12.64
    Tasks: 1202 total,   3 running, 1187 sleeping,  11 stopped,   1 zombie
    %Cpu0  :  59.9/2.4    
62[||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||               
                       ]
    %Cpu1  :  18.9/3.2    22[||||||||||||||||||||||                             
                                                 ]
    %Cpu2  : 100.0/0.0   
100[||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||]
    %Cpu3  :  28.0/5.0    33[|||||||||||||||||||||||||||||||||                  
                                                 ]
    %Cpu4  : 100.0/0.0   
100[||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||]
    %Cpu5  :  28.4/6.0    34[||||||||||||||||||||||||||||||||||                 
                                                 ]
    %Cpu6  :  27.7/7.0    35[|||||||||||||||||||||||||||||||||||                
                                                 ]
    %Cpu7  :  66.4/1.7    
68[||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||         
                       ]
    %Cpu8  : 100.0/0.0   
100[||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||]
    %Cpu9  :  64.5/1.0    
66[||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||           
                       ]
    %Cpu10 :  31.9/2.3    34[||||||||||||||||||||||||||||||||||                 
                                                 ]
    %Cpu11 :  28.2/4.1    32[||||||||||||||||||||||||||||||||                   
                                                 ]
    %Cpu12 :   2.4/14.0   16[||||||||||||||||                                   
                                                 ]
    %Cpu13 :  26.5/4.5    31[|||||||||||||||||||||||||||||||                    
                                                 ]
    %Cpu14 :  19.2/3.8    23[|||||||||||||||||||||||                            
                                                 ]
    %Cpu15 :  13.5/47.6   
61[||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||               
                       ]
    KiB Mem : 65698984 total,  2975420 free, 54425204 used,  8298360 buff/cache
    KiB Swap: 98304000 total, 80390640 free, 17913356 used.  9423384 avail Mem 

Even with a load of 18 on the 16 cores, my desktop remains as
responsive as ever, so the 60 VMs that are also running there don't
bother me at all.

By the time I finished this letter, eight builds on Fedora 23, 24, 25,
and Rawhide with both cc and c99 had completed; all passed the
validation suite.

-------------------------------------------------------------------------------
- Nelson H. F. Beebe                    Tel: +1 801 581 5254                  -
- University of Utah                    FAX: +1 801 581 4148                  -
- Department of Mathematics, 110 LCB    Internet e-mail: address@hidden  -
- 155 S 1400 E RM 233                       address@hidden  address@hidden -
- Salt Lake City, UT 84112-0090, USA    URL: http://www.math.utah.edu/~beebe/ -
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