From: "Morten Brørup" <mb@smartsharesystems.com>
To: <dev@dpdk.org>
Cc: <mattias.ronnblom@ericsson.com>, <david.marchand@redhat.com>
Subject: [RFC] eal: per-thread constructors/destructors
Date: Sun, 18 Dec 2022 11:01:12 +0100 [thread overview]
Message-ID: <98CBD80474FA8B44BF855DF32C47DC35D875C4@smartserver.smartshare.dk> (raw)
This RFC introduces per-thread constructors/destructors:
* Per-thread constructors are functions called as the first thing from newly created threads. This can be used to initialize variables in thread-local storage, variables depending on the (tid_t) thread id, and to call setup functions that must be called from the thread itself.
* Per-thread destructors are functions called (from the thread) as the last thing when a thread ends.
At this time, I am seeking feedback on the concept and the proposed limitations.
Processes have __attribute__(constructor/destructor) to set up functions to be called before main(). Nothing similar exists for threads, so we have to design it ourselves.
The proposed per-thread constructors/destructors should not apply to all threads - only to threads created through the DPDK threads API. Agree?
DPDK has the RTE_INIT()/RTE_FINI() macros for adding process constructors/destructors at build time, so I propose a similar API, i.e. adding RTE_THREAD_INIT() and RTE_THREAD_FINI() macros to build a list of per-thread constructors and destructors at build time.
Two functions that call the list of per-thread constructors respectively destructors will be introduced.
The per-thread constructor function will be called from the newly created threads within DPDK:
1. EAL/SERVICE threads: In eal_thread_loop() before the loop.
2. CTRL threads: In ctrl_thread_init() before start_routine().
3. Non-EAL threads: In rte_thread_register().
Are any thread types missing in the list above?
The per-thread destructor function will also be registered by the per-thread constructor, using the POSIX pthread_cleanup_push() function.
Examples of where per-thread constructors are useful:
PRNG state initialization [1]: http://inbox.dpdk.org/dev/2a5121c7-369f-afde-0898-d45a5b368c3a@ericsson.com/
PMU event setup [2]: http://inbox.dpdk.org/dev/a059c403-8c6c-79c3-c3e9-a8c1815f5a14@ericsson.com/T/#m3d29fbc301059f007425ac148a4113e66d2ef983
Please also refer to the discussion [3] about lcore init callbacks for further thoughts. Especially the de-facto inability to establish constructors/destructors at runtime.
[3]: http://inbox.dpdk.org/dev/98CBD80474FA8B44BF855DF32C47DC35D875B6@smartserver.smartshare.dk/T/#m23b9a930a4050dc6b0305d3653754bd152c09ab7
Med venlig hilsen / Kind regards,
-Morten Brørup
next reply other threads:[~2022-12-18 10:01 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-18 10:01 Morten Brørup [this message]
2022-12-19 15:53 ` Mattias Rönnblom
2022-12-21 16:12 ` David Marchand
2022-12-21 17:54 ` Tyler Retzlaff
2022-12-21 18:56 ` Mattias Rönnblom
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