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fish-shell/src/topic_monitor.h

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Introduce topic monitoring topic_monitor allows for querying changes posted to one or more topics, initially sigchld. This will eventually replace the waitpid logic in process_mark_finished_children(). Comment from the new header: Topic monitoring support. Topics are conceptually "a thing that can happen." For example, delivery of a SIGINT, a child process exits, etc. It is possible to post to a topic, which means that that thing happened. Associated with each topic is a current generation, which is a 64 bit value. When you query a topic, you get back a generation. If on the next query the generation has increased, then it indicates someone posted to the topic. For example, if you are monitoring a child process, you can query the sigchld topic. If it has increased since your last query, it is possible that your child process has exited. Topic postings may be coalesced. That is there may be two posts to a given topic, yet the generation only increases by 1. The only guarantee is that after a topic post, the current generation value is larger than any value previously queried. Tying this all together is the topic_monitor_t. This provides the current topic generations, and also provides the ability to perform a blocking wait for any topic to change in a particular topic set. This is the real power of topics: you can wait for a sigchld signal OR a thread exit.
2019-02-02 23:39:04 +00:00
#ifndef FISH_TOPIC_MONITOR_H
#define FISH_TOPIC_MONITOR_H
Initial Rust commit
2023-01-14 22:56:24 +00:00
#include "config.h"
topic_monitor to use binary semaphore instead of self-pipe With the prior commit, the topic_monitor only writes to the pipe if a thread is known to be waiting. This is effectively a binary semaphore, and on systems that support anon semaphores (yes Linux, but not Mac) we can use them. These are more efficient than self-pipes. We add a binary_semaphore_t class which uses sem_t if sem_init succeeds, and a self-pipe if it fails. On Linux the seq_echo benchmark (run 1024 times) goes from 12.40 seconds to 11.59 seconds, about an 11% improvement.
2020-08-20 20:57:51 +00:00
Initial Rust commit
2023-01-14 22:56:24 +00:00
#include <stdint.h>
Introduce topic monitoring topic_monitor allows for querying changes posted to one or more topics, initially sigchld. This will eventually replace the waitpid logic in process_mark_finished_children(). Comment from the new header: Topic monitoring support. Topics are conceptually "a thing that can happen." For example, delivery of a SIGINT, a child process exits, etc. It is possible to post to a topic, which means that that thing happened. Associated with each topic is a current generation, which is a 64 bit value. When you query a topic, you get back a generation. If on the next query the generation has increased, then it indicates someone posted to the topic. For example, if you are monitoring a child process, you can query the sigchld topic. If it has increased since your last query, it is possible that your child process has exited. Topic postings may be coalesced. That is there may be two posts to a given topic, yet the generation only increases by 1. The only guarantee is that after a topic post, the current generation value is larger than any value previously queried. Tying this all together is the topic_monitor_t. This provides the current topic generations, and also provides the ability to perform a blocking wait for any topic to change in a particular topic set. This is the real power of topics: you can wait for a sigchld signal OR a thread exit.
2019-02-02 23:39:04 +00:00
Simplify topic monitoring The topic monitor allows a client to wait for multiple events, e.g. sigchld or an internal process exit. Prior to this change a client had to specify the list of generations and the list of topics they are interested in. Simplify this to just the list of generations, with a max-value generation meaning the topic is not interesting. Also remove the use of enum_set and enum_array, it was too complex for what it offered.
2020-08-07 02:00:53 +00:00
using generation_t = uint64_t;
Initial Rust commit
2023-01-14 22:56:24 +00:00
#if INCLUDE_RUST_HEADERS
topic_monitor to use binary semaphore instead of self-pipe With the prior commit, the topic_monitor only writes to the pipe if a thread is known to be waiting. This is effectively a binary semaphore, and on systems that support anon semaphores (yes Linux, but not Mac) we can use them. These are more efficient than self-pipes. We add a binary_semaphore_t class which uses sem_t if sem_init succeeds, and a self-pipe if it fails. On Linux the seq_echo benchmark (run 1024 times) goes from 12.40 seconds to 11.59 seconds, about an 11% improvement.
2020-08-20 20:57:51 +00:00
Initial Rust commit
2023-01-14 22:56:24 +00:00
#include "topic_monitor.rs.h"
topic_monitor to use binary semaphore instead of self-pipe With the prior commit, the topic_monitor only writes to the pipe if a thread is known to be waiting. This is effectively a binary semaphore, and on systems that support anon semaphores (yes Linux, but not Mac) we can use them. These are more efficient than self-pipes. We add a binary_semaphore_t class which uses sem_t if sem_init succeeds, and a self-pipe if it fails. On Linux the seq_echo benchmark (run 1024 times) goes from 12.40 seconds to 11.59 seconds, about an 11% improvement.
2020-08-20 20:57:51 +00:00
Initial Rust commit
2023-01-14 22:56:24 +00:00
#else
topic_monitor to use binary semaphore instead of self-pipe With the prior commit, the topic_monitor only writes to the pipe if a thread is known to be waiting. This is effectively a binary semaphore, and on systems that support anon semaphores (yes Linux, but not Mac) we can use them. These are more efficient than self-pipes. We add a binary_semaphore_t class which uses sem_t if sem_init succeeds, and a self-pipe if it fails. On Linux the seq_echo benchmark (run 1024 times) goes from 12.40 seconds to 11.59 seconds, about an 11% improvement.
2020-08-20 20:57:51 +00:00
Initial Rust commit
2023-01-14 22:56:24 +00:00
// Hacks to allow us to compile without Rust headers.
struct generation_list_t {
uint64_t sighupint;
uint64_t sigchld;
uint64_t internal_exit;
topic_monitor to use binary semaphore instead of self-pipe With the prior commit, the topic_monitor only writes to the pipe if a thread is known to be waiting. This is effectively a binary semaphore, and on systems that support anon semaphores (yes Linux, but not Mac) we can use them. These are more efficient than self-pipes. We add a binary_semaphore_t class which uses sem_t if sem_init succeeds, and a self-pipe if it fails. On Linux the seq_echo benchmark (run 1024 times) goes from 12.40 seconds to 11.59 seconds, about an 11% improvement.
2020-08-20 20:57:51 +00:00
};
Initial Rust commit
2023-01-14 22:56:24 +00:00
#endif
Introduce topic monitoring topic_monitor allows for querying changes posted to one or more topics, initially sigchld. This will eventually replace the waitpid logic in process_mark_finished_children(). Comment from the new header: Topic monitoring support. Topics are conceptually "a thing that can happen." For example, delivery of a SIGINT, a child process exits, etc. It is possible to post to a topic, which means that that thing happened. Associated with each topic is a current generation, which is a 64 bit value. When you query a topic, you get back a generation. If on the next query the generation has increased, then it indicates someone posted to the topic. For example, if you are monitoring a child process, you can query the sigchld topic. If it has increased since your last query, it is possible that your child process has exited. Topic postings may be coalesced. That is there may be two posts to a given topic, yet the generation only increases by 1. The only guarantee is that after a topic post, the current generation value is larger than any value previously queried. Tying this all together is the topic_monitor_t. This provides the current topic generations, and also provides the ability to perform a blocking wait for any topic to change in a particular topic set. This is the real power of topics: you can wait for a sigchld signal OR a thread exit.
2019-02-02 23:39:04 +00:00
#endif
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