[ViewVC] Diff of: cvs/libeio/eio.pod

Comparing libeio/eio.pod (file contents):
Revision 1.7 by root, Sun Jun 5 22:44:30 2011 UTC vs.
Revision 1.9 by root, Sun Jun 5 23:07:46 2011 UTC

 C<want_poll> you would write a single byte, in C<done_poll> you would try
 to read that byte, and in the callback for the read end, you would call
 C<eio_poll>. The race is avoided here because the event loop should invoke
 your callback again and again until the byte has been read (as the pipe
 read callback does not read it, only C<done_poll>).
-=head2 CONFIGURATION
-The functions in this section can sometimes be useful, but the default
-configuration will do in most case, so you should skip this section on
-first reading.
-=over 4
-=item eio_set_max_poll_time (eio_tstamp nseconds)
-This causes C<eio_poll ()> to return after it has detected that it was
-running for C<nsecond> seconds or longer (this number can be fractional).
-This can be used to limit the amount of time spent handling eio requests,
-for example, in interactive programs, you might want to limit this time to
-C<0.01> seconds or so.
-Note that:
-a) libeio doesn't know how long your request callbacks take, so the time
-spent in C<eio_poll> is up to one callback invocation longer then this
-interval.
-b) this is implemented by calling C<gettimeofday> after each request,
-which can be costly.
-c) at least one request will be handled.
-=item eio_set_max_poll_reqs (unsigned int nreqs)
-When C<nreqs> is non-zero, then C<eio_poll> will not handle more than
-C<nreqs> requests per invocation. This is a less costly way to limit the
-amount of work done by C<eio_poll> then setting a time limit.
-If you know your callbacks are generally fast, you could use this to
-encourage interactiveness in your programs by setting it to C<10>, C<100>
-or even C<1000>.
-=item eio_set_min_parallel (unsigned int nthreads)
-Make sure libeio can handle at least this many requests in parallel. It
-might be able handle more.
-=item eio_set_max_parallel (unsigned int nthreads)
-Set the maximum number of threads that libeio will spawn.
-=item eio_set_max_idle (unsigned int nthreads)
-Libeio uses threads internally to handle most requests, and will start and stop threads on demand.
-This call can be used to limit the number of idle threads (threads without
-work to do): libeio will keep some threads idle in preparation for more
-requests, but never longer than C<nthreads> threads.
-In addition to this, libeio will also stop threads when they are idle for
-a few seconds, regardless of this setting.
-=item unsigned int eio_nthreads ()
-Return the number of worker threads currently running.
-=item unsigned int eio_nreqs ()
-Return the number of requests currently handled by libeio. This is the
-total number of requests that have been submitted to libeio, but not yet
-destroyed.
-=item unsigned int eio_nready ()
-Returns the number of ready requests, i.e. requests that have been
-submitted but have not yet entered the execution phase.
-=item unsigned int eio_npending ()
-Returns the number of pending requests, i.e. requests that have been
-executed and have results, but have not been finished yet by a call to
-C<eio_poll>).
-=back
 =head1 HIGH LEVEL REQUEST API
 Libeio has both a high-level API, which consists of calling a request
 These requests are specific to libeio and do not correspond to any OS call.
 =over 4
-=item eio_mtouch    (void *addr, size_t length, int flags, int pri, eio_cb cb, void *data)
+=item eio_mtouch (void *addr, size_t length, int flags, int pri, eio_cb cb, void *data)
+Reads (C<flags == 0>) or modifies (C<flags == EIO_MT_MODIFY) the given
+memory area, page-wise, that is, it reads (or reads and writes back) the
+first octet of every page that spans the memory area.
+This can be used to page in some mmapped file, or dirty some pages. Note
+that dirtying is an unlocked read-write access, so races can ensue when
+the some other thread modifies the data stored in that memory area.
-=item eio_custom    (void (*)(eio_req *) execute, int pri, eio_cb cb, void *data)
+=item eio_custom (void (*)(eio_req *) execute, int pri, eio_cb cb, void *data)
 Executes a custom request, i.e., a user-specified callback.
 The callback gets the C<eio_req *> as parameter and is expected to read
 and modify any request-specific members. Specifically, it should set C<<
     req->result = open (req->data, O_RDONLY);
   }
   eio_custom (my_open, 0, my_open_done, "/etc/passwd");
-=item eio_busy      (eio_tstamp delay, int pri, eio_cb cb, void *data)
+=item eio_busy (eio_tstamp delay, int pri, eio_cb cb, void *data)
 This is a a request that takes C<delay> seconds to execute, but otherwise
 does nothing - it simply puts one of the worker threads to sleep for this
 long.
 This request can be used to artificially increase load, e.g. for debugging
 or benchmarking reasons.
-=item eio_nop       (int pri, eio_cb cb, void *data)
+=item eio_nop (int pri, eio_cb cb, void *data)
 This request does nothing, except go through the whole request cycle. This
 can be used to measure latency or in some cases to simplify code, but is
 not really of much use.
 zero
 #TODO
+=head2 CONFIGURATION
+The functions in this section can sometimes be useful, but the default
+configuration will do in most case, so you should skip this section on
+first reading.
+=over 4
+=item eio_set_max_poll_time (eio_tstamp nseconds)
+This causes C<eio_poll ()> to return after it has detected that it was
+running for C<nsecond> seconds or longer (this number can be fractional).
+This can be used to limit the amount of time spent handling eio requests,
+for example, in interactive programs, you might want to limit this time to
+C<0.01> seconds or so.
+Note that:
+a) libeio doesn't know how long your request callbacks take, so the time
+spent in C<eio_poll> is up to one callback invocation longer then this
+interval.
+b) this is implemented by calling C<gettimeofday> after each request,
+which can be costly.
+c) at least one request will be handled.
+=item eio_set_max_poll_reqs (unsigned int nreqs)
+When C<nreqs> is non-zero, then C<eio_poll> will not handle more than
+C<nreqs> requests per invocation. This is a less costly way to limit the
+amount of work done by C<eio_poll> then setting a time limit.
+If you know your callbacks are generally fast, you could use this to
+encourage interactiveness in your programs by setting it to C<10>, C<100>
+or even C<1000>.
+=item eio_set_min_parallel (unsigned int nthreads)
+Make sure libeio can handle at least this many requests in parallel. It
+might be able handle more.
+=item eio_set_max_parallel (unsigned int nthreads)
+Set the maximum number of threads that libeio will spawn.
+=item eio_set_max_idle (unsigned int nthreads)
+Libeio uses threads internally to handle most requests, and will start and stop threads on demand.
+This call can be used to limit the number of idle threads (threads without
+work to do): libeio will keep some threads idle in preparation for more
+requests, but never longer than C<nthreads> threads.
+In addition to this, libeio will also stop threads when they are idle for
+a few seconds, regardless of this setting.
+=item unsigned int eio_nthreads ()
+Return the number of worker threads currently running.
+=item unsigned int eio_nreqs ()
+Return the number of requests currently handled by libeio. This is the
+total number of requests that have been submitted to libeio, but not yet
+destroyed.
+=item unsigned int eio_nready ()
+Returns the number of ready requests, i.e. requests that have been
+submitted but have not yet entered the execution phase.
+=item unsigned int eio_npending ()
+Returns the number of pending requests, i.e. requests that have been
+executed and have results, but have not been finished yet by a call to
+C<eio_poll>).
+=back
 =head1 EMBEDDING
 Libeio can be embedded directly into programs. This functionality is not
 documented and not (yet) officially supported.

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Comparing libeio/eio.pod (file contents): Revision 1.7 by root, Sun Jun 5 22:44:30 2011 UTC vs. Revision 1.9 by root, Sun Jun 5 23:07:46 2011 UTC

Diff Legend

Comparing libeio/eio.pod (file contents):
Revision 1.7 by root, Sun Jun 5 22:44:30 2011 UTC vs.
Revision 1.9 by root, Sun Jun 5 23:07:46 2011 UTC