diff options
author | Vladimir Chtchetkine <vchtchetkine@google.com> | 2010-11-15 11:02:49 -0800 |
---|---|---|
committer | Vladimir Chtchetkine <vchtchetkine@google.com> | 2010-11-16 08:19:43 -0800 |
commit | d8ba2ae8942abd9757338fc110ce6d215c486b1c (patch) | |
tree | dbb6bd7366d499b7396388169f3703cac329df33 /iolooper.h | |
parent | b94cfb86ee0337cf4454161798741076ee007688 (diff) | |
download | external_qemu-d8ba2ae8942abd9757338fc110ce6d215c486b1c.zip external_qemu-d8ba2ae8942abd9757338fc110ce6d215c486b1c.tar.gz external_qemu-d8ba2ae8942abd9757338fc110ce6d215c486b1c.tar.bz2 |
Implement absoule wait in iolooper
Change-Id: I514ffe11bcdac2fe3c6b44998892d9a604b9966f
Diffstat (limited to 'iolooper.h')
-rw-r--r-- | iolooper.h | 35 |
1 files changed, 35 insertions, 0 deletions
@@ -17,11 +17,46 @@ void iolooper_del_read( IoLooper* iol, int fd ); void iolooper_del_write( IoLooper* iol, int fd ); int iolooper_poll( IoLooper* iol ); +/* Wrapper around select() + * Return: + * > 0 in case an I/O has occurred, or < 0 on error, or 0 on timeout with + * errno set to ETIMEDOUT. + */ int iolooper_wait( IoLooper* iol, int64_t duration ); int iolooper_is_read( IoLooper* iol, int fd ); int iolooper_is_write( IoLooper* iol, int fd ); /* Returns 1 if this IoLooper has one or more file descriptor to interact with */ int iolooper_has_operations( IoLooper* iol ); +/* Gets current time in milliseconds. + * Return: + * Number of milliseconds corresponded to the current time on success, or -1 + * on failure. + */ +int64_t iolooper_now(void); +/* Waits for an I/O to occur before specific absolute time. + * This routine should be used (instead of iolooper_wait) in cases when multiple + * sequential I/O should be completed within given time interval. For instance, + * consider the scenario, when "server" does two sequential writes, and "client" + * now has to read data transferred with these two distinct writes. It might be + * wasteful to do two reads, each with the same (large) timeout. Instead, it + * would be better to assign a deadline for both reads before the first read, + * and call iolooper_wait_absoulte with the same deadline value: + * int64_t deadline = iolooper_now() + TIMEOUT; + * if (iolooper_wait_absoulte(iol, deadline)) { + * // Process first buffer. + * (iolooper_wait_absoulte(iol, deadline)) { + * // Process second read + * } + * } + * Param: + * iol IoLooper instance for an I/O. + * deadline Deadline (absoulte time in milliseconds) before which an I/O should + * occur. + * Return: + * Number of I/O descriptors set in iol, if an I/O has occurred, 0 if no I/O + * occurred before the deadline, or -1 on error. + */ +int iolooper_wait_absolute(IoLooper* iol, int64_t deadline); #endif /* IOLOOPER_H */ |