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Issue 842841 link

Starred by 2 users
Status: Untriaged
Owner: ----
Cc:
vapier@chromium.org
Components:
EstimatedDays: ----
NextAction: ----
OS: Chrome
Pri: 3
Type: Bug



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should we avoid running multiple instances of "logger" continuously?

Project Member Reported by semenzato@chromium.org, May 14 2018 
I just noticed these:

localhost autotest # ps auxwww | grep logger | grep -v grep
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND                  
syslog    1858  0.0  0.0   6496   912 ?        S    11:12   0:00 /usr/bin/logger --priority daemon err --tag shill
root      2976  0.0  0.0   4252   640 ?        S    11:12   0:00 logger -t tlsdate

I noticed them because I was about to add another one.

So that's 1.5MB of RSS, versus probably just a few kilobytes of libc if we called syslog directly.  Do we care?

It would be nice if we could get an fd for syslog output, and redirect stderr to it... but unfortunately that's not how it works---syslog takes a format string and args, and I think it prepends stuff to each line (time stamp, etc.) so exposing an fd might require a separate thread reading from it... ouch... oh well.

Comment 1 by semenzato@chromium.org, May 14 2018 

How much of that RSS is shared?  For instance, libc text.

Same question for these /bin/sh instances.

localhost autotest # ps auxwww | grep /bin/sh                                  
root      2071  0.0  0.0   4328  1572 ?        Ss   11:12   0:00 /bin/sh /usr/bin/periodic_scheduler 3600 14400 crash_sender /sbin/crash_sender
root      2100  0.0  0.0   4328  1488 ?        Ss   11:12   0:00 /bin/sh /usr/bin/periodic_scheduler 86400 600 cleanup_logs /usr/sbin/chromeos-cleanup-logs
root      2812  0.0  0.0   4328   840 ?        Ss   11:12   0:00 /bin/sh -e /proc/self/fd/9
root      2846  0.0  0.0   4328  1408 ?        Ss   11:12   0:00 /bin/sh /usr/bin/periodic_scheduler 3600 60 cros-machine-id-regen /usr/sbin/cros-machine-id-regen -r periodic -t 21600
root      2986  0.0  0.0   4328  1516 ?        Ss   11:12   0:00 /bin/sh /usr/bin/periodic_scheduler 21600 3600 trim chromeos-trim

Comment 2 by vapier@chromium.org, May 15 2018 

would it be good to get rid of every instance of `logger` in the system ?  definitely.  unfortunately, we don't have a solution for its replacement (connecting stdout/stderr directly to the /dev/logger unix socket with tags added -- it isn't just fd-to-fd), so logger remains.

can we try to have a single `logger` process that handles all of these ?  not with the current tooling, and i'm not sure that doing any work to implement this would be worthwhile instead of just going straight to the optimal solution.

as you noted, the RSS isn't entirely unique, but you'd have to look at something like smaps to find out more.

similarly for our shell replacement for a crond.  we might be at the point of evaluating existing cron implementations, or writing our (minimal) one.
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