Fix spurious "Scheduling: ..." workunits with remote caching #12973
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[ci skip-build-wheels]
…parent workunit. [ci skip-build-wheels]
# Building wheels and fs_util will be skipped. Delete if not intended. [ci skip-build-wheels]
stuhood
commented
Sep 21, 2021
| @@ -77,7 +77,7 @@ impl AsyncSemaphore { | |||
| res | |||
| } | |||
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| async fn acquire(&self) -> Permit<'_> { | |||
| pub async fn acquire(&self) -> Permit<'_> { | |||
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This was private from way back in the day when Future combinators were widely used. In an async-await world, it's easy to see how to use it correctly.
jsirois
approved these changes
Sep 21, 2021
stuhood
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Sep 21, 2021
…ild#12973) pantsbuild#12369 adjusted the workunit graph to have the `BoundedCommandRunner` mark (what it thought was) its parent workunit as blocking while waiting to acquire a slot on the semaphore. But when pantsbuild#12748 fixed rendering of parent workunits, we experienced a regression in rendering with remote caching enabled: "Scheduling: ..." workunits were rendered when a process was blocked. pantsbuild#12369 contained a bug: the workunit being marked blocked by the `BoundedCommandRunner` was not always it's direct parent: in particular, under remote caching the workunit being marked blocking was in fact its grandparent. Marking that workunit blocked had no effect, because its child (the parent of the semaphore acquisition) would still cause it to render. To fix that, we move back to directly creating a workunit for `BoundedCommandRunner` semaphore acquisition, rather than marking the inbound workunit blocked. This also has the benefit of recording how long processes waited to acquire slots. This bug is to some degree an indictment of explicitly passing workunits to improve clarity... but on the other hand, it also seems to more strongly encourage operating on workunits that you have created, and which are living on your stack. # Building wheels and fs_util will be skipped. Delete if not intended. [ci skip-build-wheels]
stuhood
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Sep 21, 2021
…ick of #12973) (#12975) #12369 adjusted the workunit graph to have the `BoundedCommandRunner` mark (what it thought was) its parent workunit as blocking while waiting to acquire a slot on the semaphore. But when #12748 fixed rendering of parent workunits, we experienced a regression in rendering with remote caching enabled: "Scheduling: ..." workunits were rendered when a process was blocked. #12369 contained a bug: the workunit being marked blocked by the `BoundedCommandRunner` was not always it's direct parent: in particular, under remote caching the workunit being marked blocking was in fact its grandparent. Marking that workunit blocked had no effect, because its child (the parent of the semaphore acquisition) would still cause it to render. To fix that, we move back to directly creating a workunit for `BoundedCommandRunner` semaphore acquisition, rather than marking the inbound workunit blocked. This also has the benefit of recording how long processes waited to acquire slots. This bug is to some degree an indictment of explicitly passing workunits to improve clarity... but on the other hand, it also seems to more strongly encourage operating on workunits that you have created, and which are living on your stack. [ci skip-build-wheels]
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#12369 adjusted the workunit graph to have the
BoundedCommandRunnermark (what it thought was) its parent workunit as blocking while waiting to acquire a slot on the semaphore. But when #12748 fixed rendering of parent workunits, we experienced a regression in rendering with remote caching enabled: "Scheduling: ..." workunits were rendered when a process was blocked.#12369 contained a bug: the workunit being marked blocked by the
BoundedCommandRunnerwas not always its direct parent: in particular, under remote caching the workunit being marked blocking was in fact its grandparent. Marking that workunit blocked had no effect, because its child (the parent of the semaphore acquisition) would still cause it to render.To fix that, we move back to directly creating a workunit for
BoundedCommandRunnersemaphore acquisition, rather than marking the inbound workunit blocked. This also has the benefit of recording how long processes waited to acquire slots.This bug is to some degree an indictment of explicitly passing workunits to improve clarity... but on the other hand, it also seems to more strongly encourage operating on workunits that you have created, and which are living on your stack.