A little more information as a result of creating a wrapper script to record git invocations. This is what I see every hour (note that the cl-update cron job runs at 29 minutes after the hour):
Mon Sep 14 13:29:10 CDT 2015
/usr/bin/git --git-dir /usr/portage/.git --work-tree /usr/portage status -b --porcelain
0.48user 2.91system 1:55.45elapsed 2%CPU (0avgtext+0avgdata 170992maxresident)k
554352inputs+0outputs (37major+7658minor)pagefaults 0swaps
Mon Sep 14 13:31:06 CDT 2015
/usr/bin/git --git-dir /var/lib/layman/calculate/.git --work-tree /var/lib/layman/calculate status -b --porcelain
0.03user 0.15system 0:04.83elapsed 3%CPU (0avgtext+0avgdata 21632maxresident)k
52848inputs+0outputs (25major+797minor)pagefaults 0swaps
Mon Sep 14 13:31:11 CDT 2015
/usr/bin/git --git-dir /var/lib/layman/distros/.git --work-tree /var/lib/layman/distros status -b --porcelain
0.00user 0.00system 0:00.58elapsed 1%CPU (0avgtext+0avgdata 13216maxresident)k
2968inputs+0outputs (4major+173minor)pagefaults 0swaps
Mon Sep 14 14:29:39 CDT 2015
/usr/bin/git --git-dir /usr/portage/.git --work-tree /usr/portage status -b --porcelain
0.53user 4.09system 9:27.24elapsed 0%CPU (0avgtext+0avgdata 170528maxresident)k
940584inputs+0outputs (13659major+19856minor)pagefaults 0swaps
Mon Sep 14 14:39:07 CDT 2015
/usr/bin/git --git-dir /var/lib/layman/calculate/.git --work-tree /var/lib/layman/calculate status -b --porcelain
0.02user 0.16system 0:05.47elapsed 3%CPU (0avgtext+0avgdata 21552maxresident)k
59584inputs+0outputs (28major+807minor)pagefaults 0swaps
Mon Sep 14 14:39:13 CDT 2015
/usr/bin/git --git-dir /var/lib/layman/distros/.git --work-tree /var/lib/layman/distros status -b --porcelain
0.00user 0.00system 0:00.25elapsed 2%CPU (0avgtext+0avgdata 13216maxresident)k
3224inputs+0outputs (8major+170minor)pagefaults 0swaps
Mon Sep 14 15:29:09 CDT 2015
/usr/bin/git --git-dir /usr/portage/.git --work-tree /usr/portage status -b --porcelain
0.52user 2.59system 2:03.44elapsed 2%CPU (0avgtext+0avgdata 171456maxresident)k
653944inputs+0outputs (27major+7794minor)pagefaults 0swaps
Mon Sep 14 15:31:14 CDT 2015
/usr/bin/git --git-dir /var/lib/layman/calculate/.git --work-tree /var/lib/layman/calculate status -b --porcelain
0.03user 0.15system 0:04.36elapsed 4%CPU (0avgtext+0avgdata 21632maxresident)k
54480inputs+0outputs (26major+803minor)pagefaults 0swaps
Mon Sep 14 15:31:18 CDT 2015
/usr/bin/git --git-dir /var/lib/layman/distros/.git --work-tree /var/lib/layman/distros status -b --porcelain
0.00user 0.00system 0:00.21elapsed 3%CPU (0avgtext+0avgdata 13264maxresident)k
2968inputs+0outputs (4major+175minor)pagefaults 0swaps
Mon Sep 14 16:29:10 CDT 2015
/usr/bin/git --git-dir /usr/portage/.git --work-tree /usr/portage status -b --porcelain
0.48user 2.79system 1:58.98elapsed 2%CPU (0avgtext+0avgdata 171616maxresident)k
627144inputs+0outputs (32major+7796minor)pagefaults 0swaps
Mon Sep 14 16:31:10 CDT 2015
/usr/bin/git --git-dir /var/lib/layman/calculate/.git --work-tree /var/lib/layman/calculate status -b --porcelain
0.02user 0.15system 0:04.04elapsed 4%CPU (0avgtext+0avgdata 21584maxresident)k
54504inputs+0outputs (27major+811minor)pagefaults 0swaps
Mon Sep 14 16:31:14 CDT 2015
/usr/bin/git --git-dir /var/lib/layman/distros/.git --work-tree /var/lib/layman/distros status -b --porcelain
0.00user 0.00system 0:00.22elapsed 3%CPU (0avgtext+0avgdata 13248maxresident)k
2968inputs+0outputs (4major+174minor)pagefaults 0swaps
My concern is that every hour this git update for /usr/portage does a very large amount of disk reads in spite of the fact that I’ve configured my updates to happen only once very day (my /var/log/calculate/lastcommand.log updates once per day). This really kills responsiveness on my laptop (Dell E6500 w/4 GB memory).