Need a big optimization for Windows

[OshotOkill]

Do you want to request a feature or report a bug?

Feature

What is the current behavior?

I've tested a lot about the installation speed between MacOS and Windows. According to the results it seems that yarn has far less optimizations for Windows. e.g. Here are the comparisons of installing react-native :

Test Machines:

• ThinkPad X1 Carbon 4, 1TB PCI-E SSD, 16GB Memory
• MacBook Air 2014, 256GB SSD, 4GB Memory

No cache & same network environment

MacOS

npm@3.10.9: 1m 31s

yarn@0.15.1: 39s

Windows

npm@3.10.9: 2m 24s

yarn@0.15.1: 2m 19s

So, it seems yarn has no advantage over npm on Windows. Did anyone face with this appearance?

Please mention your node.js, yarn and operating system version.
nodejs: 6.8.0
yarn: 0.15.1
OS: Windows 10 14393.321 & MacOS 10.12

[atkawa7]

+1

[Daniel15]

Hi @OshotOkill! Thanks for trying Yarn. Are you using Cygwin or WSL ("Bash on Ubuntu on Windows")? Both are known to have pretty bad disk IO performance.

Also, React Native has a huge number of files so copying them into node_modules is pretty slow, and disk IO for lots of little files on Windows is generally slower than Mac OS (which itself is slower than Linux ext4). We do have a task to experiment with hardlinks (#499) which should improve perf in this scenario.

No cache & same network environment

The main improvement with Yarn is when you have a warm cache (ie. after you've installed a package at least once), but with React Native, the huge number of files will also be a cause of some of the slowness.

[OshotOkill]

@Daniel15 Nope, I'm not using Cygwin/MinGW/MSYS2 or WSL (the latter fails due to a knotty bug).

According to your description I can assume the problem is caused by the file system (NTFS) right ? Even if a warm cache exists, the copying process still runs much slower than MacOS.

Hope the dev teams can come up with a solution ASAP. Thanks.

[fooey]

I'm seeing the same.

Do install, wipe node_modules, install

MacBookPro takes 17 seconds, my Windows machine takes 122 seconds.

[cpojer]

Somebody pointed out this might be related to anti-virus software scanning node_modules and the global yarn cache continuously. Can you try disabling it for those folders?

[OshotOkill]

@cpojer I guess they are right . I don't have any anti-virus software on my machine except the pre-installed Windows Defender, so I banned the scanning of global cache folder & my project folder and did some test:

Default: 128.08s

No scanning of cache folder: 104.43s

No scanning of project folder: 78.28s

No scanning of cache folder & project folder: 53.48s

Though it's slower than Mac for 10+s, it has a significant boost.

This should be informed from the official docs I think.

[Daniel15]

Somebody pointed out this might be related to anti-virus software scanning node_modules and the global yarn cache continuously.

Good catch! I totally forgot about this as I already have c:\src whitelisted on my computers.

@OshotOkill - Would you like to submit a pull request adding a note about antivirus apps to the website, in the Windows installation instructions? Here's the file you'd need to edit: https://github.com/yarnpkg/website/blob/master/en/docs/_installations/windows.md (you can edit it directly on Github). It'd be appreciated 😄

[fooey]

I wasn't as meticulous as @OshotOkill, but I added exceptions for my source and my node install folder, and then specifically exempted the yarn, npm and node binaries and now my fresh install time on Windows is down to 50 seconds from 122 seconds.

[OshotOkill]

@Daniel15 PR is ready. Apologize for my poor English.

[OshotOkill]

PR has been merged. Close this issue.

[voliva]

This is still painfully slow on windows, even deactivating anti-virus and Windows defender. I don't think it's just an environment issue (like this anti-virus solution) but it looks like yarn tries to copy all the files, 1-by-1 even if you install some unrelated dependency.

Why not just delete/copy the files that need to change? If I had webpack installed and is not modified when I installed rimraf, It shouldn't have to be copied again from the cache to the local node_modules folder.