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W dniu wto, 12.05.2020 o godzinie 10∶05 -0700, użytkownik Zac Medico |
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napisał: |
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> On 5/12/20 3:39 AM, Michał Górny wrote: |
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> > I'm sorry but I was asking of a more high-level implications. |
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> > |
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> > I presume that this means that more than files of more than one |
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> > package |
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> > can be merged simultaneously. However: |
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> |
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> No, an exclusive lock must be held on vardbapi._fs_lock for this. |
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> This |
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> is currently required at least to guarantee that access to the config |
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> memory file is serialized (config memory is the thing that emerge |
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> --noconfmem disables, but --noconfmem does not disable this lock). |
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> |
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> We assume that it's probably not worthwhile to try to merge files for |
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> more than one package at a time, since that would cause them to |
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> compete |
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> for IO bandwidth. |
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> |
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> > 1. Are collisions handled correctly then? i.e. if you start |
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> > installing |
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> > A, and then B, and the two packages collide will portage fail |
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> > before |
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> > starting to install any file from B? |
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> |
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> There are no guarantees here. However, the risk is minimal, since |
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> it's |
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> unlikely that a file collision of this sort would occur. file |
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> collisions |
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> are a QA problem that is generally detected and corrected log before |
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> we |
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> would encounter a collision of this sort. |
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> |
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> > 2. Are preinst/postinst phases called simultaneously or serialized? |
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> |
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> They're serialized. |
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|
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Now I'm lost here. Could you try to explain to me, without getting |
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into the deep technicalities, how parallel-install achieves better |
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speed or at doing what is non-parallel-install so slow? |
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|
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-- |
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Best regards, |
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Michał Górny |
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