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Diffstat (limited to 'open_issues/clock_gettime.mdwn')
| -rw-r--r-- | open_issues/clock_gettime.mdwn | 58 |
1 files changed, 55 insertions, 3 deletions
diff --git a/open_issues/clock_gettime.mdwn b/open_issues/clock_gettime.mdwn index bba0d171..5345ed6b 100644 --- a/open_issues/clock_gettime.mdwn +++ b/open_issues/clock_gettime.mdwn @@ -12,8 +12,60 @@ License|/fdl]]."]]"""]] [[!tag open_issue_glibc open_issue_gnumach]] -Missing clock_gettime(CLOCK_MONOTONIC) (e.g. for iceweasel) +Missing `clock_gettime(CLOCK_MONOTONIC)` (e.g. for iceweasel) -It could be a mere matter of extending the mappable clock: add it to mapped_time_value_t in gnumach, handle it in gnumach/kern/mach_clock.c, and make clock_gettime use it. +It could be a mere matter of extending the mappable clock: add it to +`mapped_time_value_t` in gnumach, handle it in `gnumach/kern/mach_clock.c`, and +make `clock_gettime` use it. -BTW, also make gettimeofday() use it, since it's way more efficient and some applications assume that it is. +BTW, also make `gettimeofday()` use it, since it's way more efficient and some +applications assume that it is. + +What about adding a nanosecond-precision clock, too? --[[tschwinge]] + +IRC, freenode, #hurd, 2011-08-26: + + < pinotree> youpi: thing is: apparently i found a simple way to have a + monotonic clock as mmap-able device inside gnumach + < pinotree> currently, in kern/mach_clock.c there's a variable 'time', + which gets increased on clock interrupt, and optionally modified by + host_set_time + < pinotree> () + < pinotree> if i add a new variable next to it, only increasing it on + interrupt but not modifying it at all otherwise, would that give me a + monotonic clock? + < pinotree> at least on sme basic tests i did, it seems it could work that + way + < youpi> yes, it should work + < braunr> sure + < youpi> and that's the way I was considering implementing it + +IRC, freenode, #hurd, 2011-09-06: + + <pinotree> yeah, i had a draft of improved idea for also handling + nanoseconds + <tschwinge> pinotree: Ah, nice, I thought about nanoseconds as well. + <tschwinge> pinotree, youpi: This memory page is all-zero by default, + right? + <tschwinge> Can't we then say that its last int is a version code, and if + it is 0 (as it is now), we only have the normal mapped time field, if it + is 1, we also have the monotonic cliock and ns precision on address 8 and + 16 (or whatever)? + <tschwinge> In case that isn't your plan anyway. + <youpi> it's all-zero, yes + <tschwinge> Or, we say if a field is != 0 it is valid. + <youpi> making the last int a version code limits the size to one page + <youpi> I was thinking a field != 0 being valid is simpler + <youpi> but it's probably a problem too + <youpi> in that glibc usually caches whether interfaces are supported + <tschwinge> Wrap-around? + <youpi> for some clocks, it may be valid that the value is 0 + <youpi> wrap-around is another issue too + <tschwinge> Well, then we can do the version-field thing, but put it right + after the current time field (address 8, I think)? + <youpi> yes + <youpi> it's a bit ugly, but it's hidden behind the structure + <tschwinge> It's not too bad, I think. + <youpi> yes + <tschwinge> And it will forever be a witness of the evolving of this + map_time interface. :-) |