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: be...@math.utah.edu - - 155 S 1400 E RM 233 be...@acm.org be...@computer.org - - Salt Lake City, UT 84112-0090, USA URL: http://www.math.utah.edu/~beebe/ - -------------------------------------------------------------------------------