how many ways to delete/de-activate a recipe's task?
i recall that richard purdie might have explained this once but i
have no idea where that post is and i need to add something to it, anyway ... how many ways are there to "delete" a task from a recipe, and what are the differences?
so far, i've seen:
1) bitbake supports a "deltask" directive
2) you can use the [noexec] task flag
3) i've also seen redefining the task with a no-op ":" command
so what are the differences, and when would someone use one over the
others? thanks.
rday
Signature · 7 lines
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Robert P. J. Day Ottawa, Ontario, CANADA
http://crashcourse.ca
Twitter: http://twitter.com/rpjday
LinkedIn: http://ca.linkedin.com/in/rpjday
========================================================================Quoted 9 lines · Robert P. J. Day
i recall that richard purdie might have explained this once but i
have no idea where that post is and i need to add something to it, anyway ... how many ways are there to "delete" a task from a recipe, and what are the differences?so far, i've seen:
1) bitbake supports a "deltask" directive
The task and all it's dependencies go away. So anything dependent on it and the things it depends on, are no longer dependent.
Quoted 1 line
2) you can use the [noexec] task flag
The task and it's dependencies remain, but nothing is executed.
Quoted 1 line
3) i've also seen redefining the task with a no-op ":" command
The task is executed and does nothing. (I believe this dumps a stamp file and the noexec does not.. but I may be wrong.)
--Mark
Quoted 5 lines
so what are the differences, and when would someone use one over the
others? thanks.rday
Quoted 14 lines · Mark Hatle
Quoted 9 lines · Robert P. J. Day
i recall that richard purdie might have explained this once but i
have no idea where that post is and i need to add something to it, anyway ... how many ways are there to "delete" a task from a recipe, and what are the differences?so far, i've seen:
1) bitbake supports a "deltask" directive
The task and all it's dependencies go away. So anything dependent on it and the things it depends on, are no longer dependent.
Quoted 8 lines
Quoted 1 line
2) you can use the [noexec] task flag
The task and it's dependencies remain, but nothing is executed.
Quoted 1 line
3) i've also seen redefining the task with a no-op ":" command
The task is executed and does nothing. (I believe this dumps a stamp file and the noexec does not.. but I may be wrong.)
What Mark said. 3) is the old way of doing 2), we added 2) to make it more efficient since there is no task execution overhead (which at one point was measurable, it may be less so now).
Cheers,
Richard
Quoted 19 lines · Richard Purdie
Quoted 18 lines · Mark Hatle
Quoted 9 lines · Robert P. J. Day
i recall that richard purdie might have explained this once but i
have no idea where that post is and i need to add something to it, anyway ... how many ways are there to "delete" a task from a recipe, and what are the differences?so far, i've seen:
1) bitbake supports a "deltask" directive
The task and all it's dependencies go away. So anything dependent on it and the things it depends on, are no longer dependent.
Quoted 1 line
2) you can use the [noexec] task flag
The task and it's dependencies remain, but nothing is executed.
Quoted 8 lines
Quoted 4 lines
Quoted 1 line
3) i've also seen redefining the task with a no-op ":" command
The task is executed and does nothing. (I believe this dumps a stamp file and the noexec does not.. but I may be wrong.)
What Mark said. 3) is the old way of doing 2), we added 2) to make it more efficient since there is no task execution overhead (which at one point was measurable, it may be less so now).
so that first part -- that 2) is a newer, tidier(?) way of doing 3)
-- is pretty much what i remember from once upon a time. good.
as for 1), i'm still confused by that explanation. say we have the
dependency chain A -> B -> C ... A depends on B which depends on C. if i "deltask B", then any dependency links which involve B will disappear, both incoming and outgoing in the DAG. but will A be adjusted to now depend on C? (i'm guessing not, just want to be sure.)
finally, is it just a matter of personal taste whether one deletes a
task using "deltask" or uses [noexec]? i'm looking at examples under OE and here are a couple.
clearly, for image.bbclass, there are a *pile* of tasks that are not
relevant, so the following makes sense:
meta/classes/image.bbclass:do_fetch[noexec] = "1" meta/classes/image.bbclass:do_unpack[noexec] = "1" meta/classes/image.bbclass:do_patch[noexec] = "1" meta/classes/image.bbclass:do_configure[noexec] = "1" meta/classes/image.bbclass:do_compile[noexec] = "1" meta/classes/image.bbclass:do_install[noexec] = "1" meta/classes/image.bbclass:do_populate_sysroot[noexec] = "1" meta/classes/image.bbclass:do_package[noexec] = "1" meta/classes/image.bbclass:do_package_qa[noexec] = "1" meta/classes/image.bbclass:do_packagedata[noexec] = "1" meta/classes/image.bbclass:do_package_write_ipk[noexec] = "1" meta/classes/image.bbclass:do_package_write_deb[noexec] = "1" meta/classes/image.bbclass:do_package_write_rpm[noexec] = "1" meta/classes/image.bbclass:do_bundle_initramfs[noexec] = "1"
similarly, for native.bbclass, the following also makes sense, but
uses "deltask":
meta/classes/native.bbclass:deltask package meta/classes/native.bbclass:deltask packagedata meta/classes/native.bbclass:deltask package_qa meta/classes/native.bbclass:deltask package_write_ipk meta/classes/native.bbclass:deltask package_write_deb meta/classes/native.bbclass:deltask package_write_rpm meta/classes/native.bbclass:deltask package_write
so why does the first use [noexec] and the second use deltask? is
there a functional difference?
rday
p.s. i believe i appreciate the difference in *mechanics* of the above. [noexec] doesn't affect the DAG of task dependencies, it simply turns off the execution of that recipe-specific task, while "deltask" affects the actual underlying task DAG.
Signature · 7 lines
========================================================================
Robert P. J. Day Ottawa, Ontario, CANADA
http://crashcourse.ca
Twitter: http://twitter.com/rpjday
LinkedIn: http://ca.linkedin.com/in/rpjday
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