Reset concurrency to the initial default #336
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Rakefile
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| require "bundler/gem_tasks" | |||
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| # Disable stderr warning output | |||
| ENV["VIPS_WARNING"] = "1" | |||
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We purposefully test behaviors that warn, so disable stderr output.
| attach_function :vips_concurrency_get, [], :int | ||
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| # Track the original default concurrency so we can reset to it. | ||
| DEFAULT_CONCURRENCY = vips_concurrency_get |
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Read the default right away so we can reset to it. (Note Vips.vips_init just above which sets the initial vips__concurrency to VIPS_CONCURRENCY or CPU count.)
| # Get the default size of libvips worker pools. | ||
| def self.concurrency_default | ||
| DEFAULT_CONCURRENCY | ||
| end |
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Useful to expose VIPS_CONCURRENCY or CPU count.
| # var or the number of hardware threads on your computer. | ||
| def self.concurrency | ||
| vips_concurrency_get | ||
| end |
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For inspection, logging, metrics, and the like.
| def self.concurrency_set n | ||
| n = DEFAULT_CONCURRENCY if n.to_i == 0 |
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Assign 0 or nil to restore the initial default.
| vips_concurrency_set n | ||
| concurrency |
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Nice to return the value that was set.
| # before Vips.init sets concurrency to the default. | ||
| DEFAULT_VIPS_CONCURRENCY = 5 | ||
| ENV["VIPS_CONCURRENCY"] = DEFAULT_VIPS_CONCURRENCY.to_s | ||
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For predictable testing. Set our own VIPS_CONCURRENCY rather than let it default to CPU count.
`Vips.concurrency_set(0)` suggests it'll set concurrency back to the default value, but it does nothing if concurrency is already set, which is always true because Vips.init has already configured thread pools. The result is that if you set concurrency to any value, setting it to zero will leave that value in place. This reads the default concurrency immediately after Vips.init so we can make good on having `concurrency_set 0` reset to default. Also allows setting `nil` to reset to default. Note that setting concurrency does not reconfigure existing thread pools. It affects thread pools spawned for future operations.
jeremy
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What a nice clean PR. Good job! |
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... I updated the CHANGELOG. |
Vips.concurrency_set(0)suggests it'll set concurrency back to thedefault value, but it does nothing if concurrency is already set, which
is always true because Vips.init has already configured thread pools.
The result is that if you set concurrency to any value, setting it to
zero will leave that value in place.
This reads the default concurrency immediately after Vips.init so we
can make good on having
concurrency_set 0reset to default. Alsoallows setting
nilto reset to default.Note that setting concurrency does not reconfigure existing thread
pools. It affects thread pools spawned for future operations.
References #335