At OLS last week, During Dave Jones Userspace Sucks presentation, Jim
Geddys and some of the Xorg guys noted that they would be able to
stop using gettimeofday
so frequently, if they had some other way to get a millisecond
resolution timer
in userspace, one that they could perhaps read from a memory mapped
page. I was
right behind them and though that seemed like a reasonable
request, so I've
taken a stab at it. This patch allows for a page to be mmaped
from /dev/rtc
character interface, the first 4 bytes of which provide a regularly
increasing
count, once every rtc interrupt. The frequency is of course
controlled by the
regular ioctls provided by the rtc driver. I've done some basic
testing on it,
and it seems to work well.
Similar functionality is already available via VDSO on
platforms that support it (currently PowerPC and AMD64?) --
seems like a better way forward.
Segher
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
