Reduce string allocations when formatting file system objects. - #8831
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Staffan Gustafsson (@powercode) Please have a look at the test failure. |
| internal void SetModule(PSModuleInfo module) | ||
| { | ||
| Module = module; | ||
| _fullName = null; // clear the cached FullName |
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Please remove the comment. Better use _cacheFullModuleName name.
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But it isn't a full module name. That name would be misleading. But sure, I can remove the comment.
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If it is not a full name what about _cachedModuleName?
I see there comment "Gets the name of the provider." So the name could be appropriate - _cachedProviderName.
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The property is FullName, so it makes sense to me that the backing property is _fullName.
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I tried to insert your comment to the name that it is a cached :-)
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Awesome. Out of curiosity: Do you have time measurements of cases where this improvement is noticeable? |
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Christoph Bergmeister (@bergmeister) It's mostly in allocations - it generates lots of extra strings, like 2 strings per item in the pipeline. I'm reasoning more in terms of steadily removing silly allocations, and fixing the worst offenders perf-wise, and eventually we will have a more snappy shell. The image below show the dotmemory view of strings allocated, grouped by callstack, when looking at the first 50000 items in the windows dir. It wasn't the biggest, but it was one of the bigger, and it was low hanging fruit. Does it make sense?
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Thanks Staffan Gustafsson (@powercode). Yes, makes sense. I agree that continous improvement will make it better over time. :) |
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Christoph Bergmeister (@bergmeister) It may seem like I'm just doing random changes, but I actually measure things now and then :) dotTrace and dotMemory are almost always running on my machine. |
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Staffan Gustafsson (@powercode) I was not questioning it, I was just curious for my own education (because knowing this also means that one will know the scenarios where PSCore is stronger than Windows PowerShell meaning that I could recommend an upgrade to clients). |
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Christoph Bergmeister (@bergmeister) Windows PowerShell is still more efficient than PowerShell Core |
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Christoph Bergmeister (@bergmeister) I'm currently working on optimizations for the formatting system, the filesystem provider, etc that makes it out-perform windows powershell with a huge margin, often like 4x. And with a memory footprint reduction of the similar size. Import-Csv is problematic, since our property abstraction is heavier that I would like it to be. Especially in cases like that, where we actually have a table, we wouldn't need to store all the metadata for each object. I haven't given it so much thought - just passed by it last fall when doing related work. I have an idea that I like to try out for Import-CSV - could drastically reduce the memory footprint. |
…Shell#8831) * Reduce string allocations when formatting file system objects by caching FullName. * Clear cache FullName when the module changes.
PR Summary
Cache FullName property in the ProviderInfo class. Causes extra string allocations for every item in the formatting pipeline.
PR Context
PR Checklist
.h,.cpp,.cs,.ps1and.psm1files have the correct copyright headerWIP:or[ WIP ]to the beginning of the title (theWIPbot will keep its status check atPendingwhile the prefix is present) and remove the prefix when the PR is ready.[feature]to your commit messages if the change is significant or affects feature tests