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authorTomas Janousek <tomi@nomi.cz>2020-11-12 10:02:44 +0000
committerjao <jao@gnu.org>2020-11-13 02:10:31 +0000
commit17b0dac481c01425651326e8814b45058cd40f06 (patch)
treecabb9394e29880b7460ae3cfbc449c53bd416722 /changelog.md
parente47cb0222eb5b152f69a18f4685726a5460f4b90 (diff)
downloadxmobar-17b0dac481c01425651326e8814b45058cd40f06.tar.gz
xmobar-17b0dac481c01425651326e8814b45058cd40f06.tar.bz2
Optimize Date plugin again (refresh timezone only once a minute)
This makes the Date plugin approximately twice as fast, and makes xmobar up to about 5–10 % faster if Date is the only active plugin. (If more expensive plugins like Network or MultiCpu are used, it doesn't make any measurable difference.) Micro-benchmark results on my HW: Date Benchmarks/Date mean 2.833 μs ( +- 16.08 ns ) Date Benchmarks/DateZonedTime mean 5.020 μs ( +- 32.91 ns ) Date Benchmarks/DateWithTimeZone mean 2.827 μs ( +- 20.52 ns ) (DateZonedTime is the original implementation and DateWithTimeZone is the implementation we had since 0.34 which never refreshes timezone.) Real-life measurements (done overnight on an idle laptop, with all measured xmobars running in parallel to ensure comparable conditions; xmobars configured to only display date and with rate 10 — once per second): $ time timeout 6h xmobar .xmobarrc-DateZonedTime real 360m0,010s user 0m9,867s sys 0m4,644s (9.867 + 4.644) / (360 * 60) = 0.000672 $ time timeout 6h xmobar .xmobarrc-Date real 360m0,008s user 0m9,535s sys 0m4,327s (9.535 + 4.327) / (360 * 60) = 0.000642 $ time timeout 6h xmobar .xmobarrc-Date-10m real 360m0,010s user 0m9,780s sys 0m4,215s (9.780 + 4.215) / (360 * 60) = 0.000648 $ time timeout 6h xmobar .xmobarrc-DateWithTimeZone real 360m0,006s user 0m9,658s sys 0m4,166s (9.658 + 4.166) / (360 * 60) = 0.000640 (.xmobarrc-Date-10m is the proposed implementation, but with timezone refresh every 10 minutes instead of every 1 minute) Interpretation of these results: * refreshing xmobar with just date takes around 650 μs * that is xmobar with just date uses around 0.065 % of CPU time * refreshing timezone takes additional cca 30 μs When we only refresh timezone once a minute, these 30 μs become 0.5 μs amortized, and that should be acceptable to even the most dedicated perfectionist :-) Fixes: a58e32f7c8af ("Revert "Optimize date plugin"") Fixes: 878db3908060 ("Optimize date plugin") Co-authored-by: Sibi Prabakaran <sibi@psibi.in>
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@@ -6,8 +6,8 @@ _New features_
_Bug fixes_
- - Fix date plugin not picking up DST and timezone changes
- (Fixed by reverting the optimization merged in 0.34).
+ - Fix date plugin not picking up DST and timezone changes (refresh
+ timezone once a minute to preserve the optimized performace of 0.34).
## Version 0.36 (August, 2020)