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Type:
Improvement
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Resolution: Won't Do
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Priority:
Major - P3
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Affects Version/s: None
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Component/s: Build
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Server Development Platform
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3
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One of the weird things I learned while working on ninja is that install is significantly faster than cp. I don't know why this is, but it is reproducible across many systems and filesystems, etc. For example, this is running on a virtual workstation (c5.4xl ubuntu 18.04 xfs):
ubuntu@ip-10-122-10-16:~$ dd if=/dev/zero of=src bs=1M count=100; sync; 100+0 records in 100+0 records out 104857600 bytes (105 MB, 100 MiB) copied, 0.189798 s, 552 MB/s ubuntu@ip-10-122-10-16:~$ for i in `seq 10`; do time install src dest; done; sync; real 0m0.061s user 0m0.000s sys 0m0.061s real 0m0.064s user 0m0.000s sys 0m0.064s real 0m0.061s user 0m0.000s sys 0m0.061s real 0m0.061s user 0m0.000s sys 0m0.061s real 0m0.061s user 0m0.000s sys 0m0.061s real 0m0.061s user 0m0.000s sys 0m0.061s real 0m0.061s user 0m0.000s sys 0m0.061s real 0m0.061s user 0m0.000s sys 0m0.061s real 0m0.061s user 0m0.000s sys 0m0.061s real 0m0.060s user 0m0.000s sys 0m0.061s ubuntu@ip-10-122-10-16:~$ for i in `seq 10`; do time cp src dest; done; sync; real 0m0.234s user 0m0.000s sys 0m0.071s real 0m0.226s user 0m0.004s sys 0m0.067s real 0m0.220s user 0m0.000s sys 0m0.073s real 0m0.211s user 0m0.000s sys 0m0.070s real 0m0.223s user 0m0.000s sys 0m0.075s real 0m0.335s user 0m0.000s sys 0m0.075s real 0m0.400s user 0m0.000s sys 0m0.073s real 0m0.400s user 0m0.004s sys 0m0.066s real 0m0.398s user 0m0.000s sys 0m0.073s real 0m0.399s user 0m0.000s sys 0m0.070s
I have tried on my laptop (WSL2 + Arch ext4 on nvme) and the results were similar. Including the weirdness of later runs of cp being slower than earlier runs. �
- is related to
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SERVER-48203 Support --install-action for Ninja builds
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- Closed
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