Public bug reported: It seems that unsetting the environment variable TZ there is a huge performance penalty calling some glibc functions, eg. time()
this has been documented here: https://blog.packagecloud.io/eng/2017/02/21/set-environment-variable- save-thousands-of-system-calls/ and I can confirm it on an amd64 system running Yakkety: $ cat time.c #include <time.h> int main(int argc, char *argv[]) { int i = 0; time_t timep; for (i = 0; i < 10000000; i++) { time(&timep); localtime(&timep); } return 0; } $ gcc -Wall -O3 time.c -o time $ time ./time real 0m7.102s user 0m2.060s sys 0m5.040s $ time TZ=:/etc/localtime ./time real 0m0.952s user 0m0.948s sys 0m0.000s $ I've set TZ in /etc/environment to have it globally defined. ** Affects: shadow (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to shadow in Ubuntu. https://bugs.launchpad.net/bugs/1669055 Title: TZ is not set by default Status in shadow package in Ubuntu: New Bug description: It seems that unsetting the environment variable TZ there is a huge performance penalty calling some glibc functions, eg. time() this has been documented here: https://blog.packagecloud.io/eng/2017/02/21/set-environment-variable- save-thousands-of-system-calls/ and I can confirm it on an amd64 system running Yakkety: $ cat time.c #include <time.h> int main(int argc, char *argv[]) { int i = 0; time_t timep; for (i = 0; i < 10000000; i++) { time(&timep); localtime(&timep); } return 0; } $ gcc -Wall -O3 time.c -o time $ time ./time real 0m7.102s user 0m2.060s sys 0m5.040s $ time TZ=:/etc/localtime ./time real 0m0.952s user 0m0.948s sys 0m0.000s $ I've set TZ in /etc/environment to have it globally defined. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/shadow/+bug/1669055/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
