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Use FileStream's ctor instead of File.Open when all access is synchronous #5680
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| @@ -43,7 +43,7 @@ private bool TryLoadManagedAssemblyMetadata() | |||
| try | |||
| { | |||
| // Try to load the file using the managed metadata reader | |||
| using (FileStream assemblyStream = File.OpenRead(_fileName)) | |||
| using (FileStream assemblyStream = new FileStream(_fileName, FileMode.Open, FileAccess.Read, FileShare.Read, 0x1000, useAsync: false)) | |||
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Can you use a named parameter for buffer size throughout?
…nous Several places in our libraries use use File.Open* methods. These are simple wrappers for FileStream's constructors, and all use the default "useAsync" value of true (this varies from the the full framework, where the default is false). When only using synchronous Stream methods, a value of true is pure overhead, as each Read/Write/Flush method needs to schedule the asynchronous operation and then block waiting for it to complete. In the few places we're using File.Open* in this manner, I've changed them to instead use FileStream's ctor directly, to avoid the unnecessary access overheads.
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For a couple of these I am concerned that we don't actually have an async API. In particular the ZipArchive ones. Those can be some pretty expensive blocking reads. |
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I agree. I think it's certainly worthwhile looking at adding additional async compression APIs. Until that happens, though, I think the changes in this PR are pure goodness. Agreed? |
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Yeah, LGTM. I filed an issue on adding APIs. |
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LGTM |
stephentoub
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Use FileStream's ctor instead of File.Open when all access is synchronous
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picenka21
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Use FileStream's ctor instead of File.Open when all access is synchronous Commit migrated from dotnet/corefx@d214ddb
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Several places in our libraries use use File.Open* methods. These are simple wrappers for FileStream's constructors, and all use the default "useAsync" value of true (this varies from the the full framework, where the default is false). When only using synchronous Stream methods, a value of true is pure overhead, as each Read/Write/Flush method needs to schedule the asynchronous operation and then block waiting for it to complete. In the few places we're using File.Open* in this manner, I've changed them to instead use FileStream's ctor directly, to avoid the unnecessary access overheads.
cc: @ericstj, @ianhays, @mellinoe