Show HN: whytime: time(1) that tells you where the wall-clock time went

time says a command took 3.8 seconds... whytime tells you where those seconds went:

 $ sudo whytime -- sh -c 'sleep 0.5; dd … oflag=dsync; curl -s -o /dev/null https://speed.cloudflare.com/…' wall 3.83s 47% blocked on network: speed.cloudflare.com:443 (1 connection) 34% fsync on ~/.cache 13% timer sleep (sleep) 4% on-CPU (curl) 2% other 

The lines always add up to 100%. When the command waits on a child or another thread, whytime follows whoever woke it up, so a shell waiting on curl is charged to the network wait curl was stuck on. The top line is what you'd have to make faster.

It can also draw a flamegraph.

Uses eBPF (Linux 5.18+)

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Comments URL: https://news.ycombinator.com/item?id=50201687

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