Debugging: Stabilize hidden classes for improved heap snapshots #8912
Comments
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@Raynos is this problem in v6 as well? Would the solution be simply adding those fields in the constructor? |
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This applies to 4.x & master. I did not check 6.x, I assume 6.x and master are the same. |
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/cc @nodejs/http |
cjihrig
added
the
good first issue
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Adding the good first contribution label. |
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Can take this one. |
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Personally, having variables defined on the prototype is more messy then defining them in the constructor. |
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@shmuga are you working on this? |
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It's also slower to define them on the prototype. It's a good idea to always define properties used statically - even as null. |
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Doing this would probably also help performance. |
res and abort fields are now defined in the constructor and not suddenly appear during the runtime. This makes hidden class stable and the heap snapshot more verbose. Ref: nodejs#8912 PR-URL: nodejs#9116
Adding all used properties in the constructor makes the hidden class stable and heap snapshots more verbose. Refs: #8912 PR-URL: #9116 Reviewed-By: Brian White <mscdex@mscdex.net> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Michaël Zasso <targos@protonmail.com>
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a2ea134 addresses this in the master. |
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Closing this for now, as the commit @thefourtheye mentioned should take care of this. |
Adding all used properties in the constructor makes the hidden class stable and heap snapshots more verbose. Refs: nodejs#8912 PR-URL: nodejs#9116 Reviewed-By: Brian White <mscdex@mscdex.net> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Michaël Zasso <targos@protonmail.com>
Adding all used properties in the constructor makes the hidden class stable and heap snapshots more verbose. Refs: nodejs#8912 PR-URL: nodejs#9116 Reviewed-By: Brian White <mscdex@mscdex.net> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Michaël Zasso <targos@protonmail.com>
Adding all used properties in the constructor makes the hidden class stable and heap snapshots more verbose. Refs: nodejs#8912 PR-URL: nodejs#9116 Reviewed-By: Brian White <mscdex@mscdex.net> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Michaël Zasso <targos@protonmail.com>
Adding all used properties in the constructor makes the hidden class stable and heap snapshots more verbose. Refs: nodejs#8912 PR-URL: nodejs#9116 Reviewed-By: Brian White <mscdex@mscdex.net> Reviewed-By: James M Snell <jasnell@gmail.com> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Michaël Zasso <targos@protonmail.com>
Currently the http client does not have stable hidden classes so it's hard to debug it.
For example:
These are two different fields that do not exist in the constructor ( https://github.com/nodejs/node/blob/master/lib/_http_client.js#L18-L202 ).
We need to add
self.res = null; self.aborted = 0;Without a stable hidden class for the
ClientRequest( one that doesn't change at runtime ) it's very hard to debug the state of a heap using a heapsnapshotThis heapsnapshot is missing the
resandabortedfields. Having these fields available would make it a lot easier to reason about the state of theClientRequest( I have a memory leak where I am leaking outbound ClientRequest instances ).I'm sure that this problem exists for a lot of other internal classes within the code.
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