[SR-8782] swift 4.2 - the write to file from 0,54 seconds became 6 seconds (the "swift" come back to regression again)

[swift-ci]

Previous ID	SR-8782
Radar	rdar://problem/44562009
Original Reporter	woodcrust (JIRA User)
Type	Bug

Attachment: Download

Environment

Linux megatron 4.15.0-23-generic #25-Ubuntu SMP Wed May 23 18:02:16 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

Additional Detail from JIRA

Votes	3
Component/s	Foundation
Labels	Bug, Performance
Assignee	@millenomi
Priority	Medium

md5: 41e66d0b088a646c5617e609a284868a

Issue Description:

Hello, sorry for my very bad english...

I like "swift" so much. But tell me please, why with each update version "swift" becomes slower ? I now afraid what next update kill "swift". Why the write to file on linux from 0,54 seconds(swift 4.1.3 and below) became 6 seconds(swift 4.2) (screenshots below) and the write to file on macOS from 0,3 seconds became 2 seconds ?

code: https://github.com/woodcrust/puffin_bench/blob/master/source/3-writeToFile/swift3.swift

[belkadan]

@swift-ci create

[swift-ci]

Comment by Mikhail Isaev (JIRA)

Looks terrible, how performance can be worse in new release?

[swift-ci]

Comment by Anton (JIRA)

I have the same issue, it is very strange that it is slower than previous version.

[swift-ci]

Comment by Oleh (JIRA)

For example also I added the write to file with posix api

[swift-ci]

Comment by Oleh (JIRA)

Linux - more regression

Swift 4.0.3 - 0.53 sec
Swift 4.2 - 6.30 sec
Swift 5.0 ~13 sec

[swift-ci]

Comment by Oleh (JIRA)

On macos with Swift 5 mid 2015 2,5 GHz Intel Core i7 - result is better

But on Linux still same very bad result as on above screenshot