[take28 0/8] kevent: Generic event handling mechanism.
Generic event handling mechanism. Kevent is a generic subsytem which allows to handle event notifications. It supports both level and edge triggered events. It is similar to poll/epoll in some cases, but it is more scalable, it is faster and allows to work with essentially eny kind of events. Events are provided into kernel through control syscall and can be read back through ring buffer or using usual syscalls. Kevent update (i.e. readiness switching) happens directly from internals of the appropriate state machine of the underlying subsytem (like network, filesystem, timer or any other). Homepage: http://tservice.net.ru/~s0mbre/old/?section=projects=kevent Documentation page: http://linux-net.osdl.org/index.php/Kevent Consider for inclusion. New benchmark, which can be a hoax though, can be found at http://tservice.net.ru/~s0mbre/blog/2006/11/30#2006_11_30 where kevent on amd64 with 1gb of ram can handle more than 7200 events per second with 8000 requests concurrency with 'ab' benchmark and lighttpd. Although I tought it should not be published due to possible errors, I decided to send it for review. With this release I start 3 days resending timeout - i.e. each third day I will send either new version (if something new was requested and agreed to be implemented) or resending with back counter started from three. When back counter hits zero after three resending I consider there is no interest in subsystem and I will stop further sending. Thanks for understanding and your time. Changes from 'take27' patchset: * made kevent default yes in non embedded case. * added falgs to callback structures - currently used to check if kevent can be requested from kernelspace only (posix timers) or userspace (all others) Changes from 'take26' patchset: * made kevent visible in config only in case of embedded setup. * added comment about KEVENT_MAX number. * spell fix. Changes from 'take25' patchset: * use timespec as timeout parameter. * added high-resolution timer to handle absolute timeouts. * added flags to waiting and initialization syscalls. * kevent_commit() has new_uidx parameter. * kevent_wait() has old_uidx parameter, which, if not equal to u->uidx, results in immediate wakeup (usefull for the case when entries are added asynchronously from kernel (not supported for now)). * added interface to mark any event as ready. * event POSIX timers support. * return -ENOSYS if there is no registered event type. * provided file descriptor must be checked for fifo type (spotted by Eric Dumazet). * signal notifications. * documentation update. * lighttpd patch updated (the latest benchmarks with lighttpd patch can be found in blog). Changes from 'take24' patchset: * new (old (new)) ring buffer implementation with kernel and user indexes. * added initialization syscall instead of opening /dev/kevent * kevent_commit() syscall to commit ring buffer entries * changed KEVENT_REQ_WAKEUP_ONE flag to KEVENT_REQ_WAKEUP_ALL, kevent wakes only first thread always if that flag is not set * KEVENT_REQ_ALWAYS_QUEUE flag. If set, kevent will be queued into ready queue instead of copying back to userspace when kevent is ready immediately when it is added. * lighttpd patch (Hail! Although nothing really outstanding compared to epoll) Changes from 'take23' patchset: * kevent PIPE notifications * KEVENT_REQ_LAST_CHECK flag, which allows to perform last check at dequeueing time * fixed poll/select notifications (were broken due to tree manipulations) * made Documentation/kevent.txt look nice in 80-col terminal * fix for copy_to_user() failure report for the first kevent (Andrew Morton) * minor function renames Changes from 'take22' patchset: * new ring buffer implementation in process' memory * wakeup-one-thread flag * edge-triggered behaviour Changes from 'take21' patchset: * minor cleanups (different return values, removed unneded variables, whitespaces and so on) * fixed bug in kevent removal in case when kevent being removed is the same as overflow_kevent (spotted by Eric Dumazet) Changes from 'take20' patchset: * new ring buffer implementation * removed artificial limit on possible number of kevents Changes from 'take19' patchset: * use __init instead of __devinit * removed 'default N' from config for user statistic * removed kevent_user_fini() since kevent can not be unloaded * use KERN_INFO for statistic output Changes from 'take18' patchset: * use __init instead of __devinit * removed 'default N' from config for user statistic * removed kevent_user_fini() since kevent can not be unloaded * use KERN_INFO for statistic output Changes from 'take17' patchset: * Use RB tree instead of hash table. At least for a web sever, frequency of addition/deletion of new kevent is comparable with number of search access, i.e. most of the time events are added, accesed only couple of times and then
[take28 0/8] kevent: Generic event handling mechanism.
Generic event handling mechanism. Kevent is a generic subsytem which allows to handle event notifications. It supports both level and edge triggered events. It is similar to poll/epoll in some cases, but it is more scalable, it is faster and allows to work with essentially eny kind of events. Events are provided into kernel through control syscall and can be read back through ring buffer or using usual syscalls. Kevent update (i.e. readiness switching) happens directly from internals of the appropriate state machine of the underlying subsytem (like network, filesystem, timer or any other). Homepage: http://tservice.net.ru/~s0mbre/old/?section=projectsitem=kevent Documentation page: http://linux-net.osdl.org/index.php/Kevent Consider for inclusion. New benchmark, which can be a hoax though, can be found at http://tservice.net.ru/~s0mbre/blog/2006/11/30#2006_11_30 where kevent on amd64 with 1gb of ram can handle more than 7200 events per second with 8000 requests concurrency with 'ab' benchmark and lighttpd. Although I tought it should not be published due to possible errors, I decided to send it for review. With this release I start 3 days resending timeout - i.e. each third day I will send either new version (if something new was requested and agreed to be implemented) or resending with back counter started from three. When back counter hits zero after three resending I consider there is no interest in subsystem and I will stop further sending. Thanks for understanding and your time. Changes from 'take27' patchset: * made kevent default yes in non embedded case. * added falgs to callback structures - currently used to check if kevent can be requested from kernelspace only (posix timers) or userspace (all others) Changes from 'take26' patchset: * made kevent visible in config only in case of embedded setup. * added comment about KEVENT_MAX number. * spell fix. Changes from 'take25' patchset: * use timespec as timeout parameter. * added high-resolution timer to handle absolute timeouts. * added flags to waiting and initialization syscalls. * kevent_commit() has new_uidx parameter. * kevent_wait() has old_uidx parameter, which, if not equal to u-uidx, results in immediate wakeup (usefull for the case when entries are added asynchronously from kernel (not supported for now)). * added interface to mark any event as ready. * event POSIX timers support. * return -ENOSYS if there is no registered event type. * provided file descriptor must be checked for fifo type (spotted by Eric Dumazet). * signal notifications. * documentation update. * lighttpd patch updated (the latest benchmarks with lighttpd patch can be found in blog). Changes from 'take24' patchset: * new (old (new)) ring buffer implementation with kernel and user indexes. * added initialization syscall instead of opening /dev/kevent * kevent_commit() syscall to commit ring buffer entries * changed KEVENT_REQ_WAKEUP_ONE flag to KEVENT_REQ_WAKEUP_ALL, kevent wakes only first thread always if that flag is not set * KEVENT_REQ_ALWAYS_QUEUE flag. If set, kevent will be queued into ready queue instead of copying back to userspace when kevent is ready immediately when it is added. * lighttpd patch (Hail! Although nothing really outstanding compared to epoll) Changes from 'take23' patchset: * kevent PIPE notifications * KEVENT_REQ_LAST_CHECK flag, which allows to perform last check at dequeueing time * fixed poll/select notifications (were broken due to tree manipulations) * made Documentation/kevent.txt look nice in 80-col terminal * fix for copy_to_user() failure report for the first kevent (Andrew Morton) * minor function renames Changes from 'take22' patchset: * new ring buffer implementation in process' memory * wakeup-one-thread flag * edge-triggered behaviour Changes from 'take21' patchset: * minor cleanups (different return values, removed unneded variables, whitespaces and so on) * fixed bug in kevent removal in case when kevent being removed is the same as overflow_kevent (spotted by Eric Dumazet) Changes from 'take20' patchset: * new ring buffer implementation * removed artificial limit on possible number of kevents Changes from 'take19' patchset: * use __init instead of __devinit * removed 'default N' from config for user statistic * removed kevent_user_fini() since kevent can not be unloaded * use KERN_INFO for statistic output Changes from 'take18' patchset: * use __init instead of __devinit * removed 'default N' from config for user statistic * removed kevent_user_fini() since kevent can not be unloaded * use KERN_INFO for statistic output Changes from 'take17' patchset: * Use RB tree instead of hash table. At least for a web sever, frequency of addition/deletion of new kevent is comparable with number of search access, i.e. most of the time events are added, accesed only couple of times and then
