Re: dtrace walltimestamp
Fabian Keil freebsd-lis...@fabiankeil.de wrote: At least on my system, timestamp offsets can only can be relied on with either kern.timecounter.hardware=TSC or with C3 states disabled, though. Measuring the elapsed time (in ms) between events that happen in roughly 1 second intervals with kern.timecounter.hardware=HPET and dev.cpu.0.cx_lowest=C2: elapsed value - Distribution - count 990 | 0 1000 |@@@ 57 1010 | 0 1020 | 0 1030 |@1 1040 | 0 elapsed avg1007 And doing the same with dev.cpu.0.cx_lowest=C3: elapsed value - Distribution - count 40 | 0 50 |@@@ 28 60 |@@@ 10 70 |@@@ 5 80 |@1 90 | 0 100 |@2 110 |@2 120 |@2 130 | 0 140 |@1 150 |@1 160 |@1 170 |@1 180 | 0 190 | 0 200 | 0 210 | 0 220 |@1 230 |@1 240 | 0 250 | 0 260 | 0 270 | 0 280 | 0 290 |@1 300 |@1 310 | 0 320 |@1 330 | 0 elapsed avg 90 Copying over some code from mips seems to fix this: http://www.freebsd.org/cgi/query-pr.cgi?pr=amd64/169379 Fabian signature.asc Description: PGP signature
Re: dtrace walltimestamp
On Sun, Aug 21, 2011 at 7:05 AM, Fabian Keil
freebsd-lis...@fabiankeil.de wrote:
Ashley Williams ashley@gmail.com wrote:
walltimestamp and timestamp don't appear to be right in BETA-1:
# dtrace -qn 'syscall::exec*:return { printf(%Y
%s\n,walltimestamp,curpsinfo-pr_psargs); }'
1970 Jan 1 10:00:00 date
1970 Jan 1 10:00:00 ping
1970 Jan 1 10:00:00 ls
I can reproduce this on amd64 with a recent HEAD, walltimestamp
is always 0, which together with the dmesg warnings seems to indicate
that it's not supported (yet).
Bug report has been filed - thanks for testing. PR - 159612 for those
interested.
# dtrace -qn 'syscall::exec*:return { printf(%Y
%s\n,timestamp,curpsinfo-pr_psargs); }'
1970 Jan 6 12:02:27 ping
1970 Jan 6 12:02:29 ls
1970 Jan 6 12:02:31 dtrace
Note that the timestamp value is relative to the time
the system is booted (I think), and not to midnight,
January 1, 1970.
Assuming your system has been running for a few days
and the offsets are right as well, the output seems fine.
Thanks for that - I did some testing on Solaris 11 and it's evident I
have misunderstood the usage of the timestamp function. The output
above, as you said, is definitely correct.
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Re: dtrace walltimestamp
Ashley Williams ashley@gmail.com wrote:
walltimestamp and timestamp don't appear to be right in BETA-1:
# dtrace -qn 'syscall::exec*:return { printf(%Y
%s\n,walltimestamp,curpsinfo-pr_psargs); }'
1970 Jan 1 10:00:00 date
1970 Jan 1 10:00:00 ping
1970 Jan 1 10:00:00 ls
I can reproduce this on amd64 with a recent HEAD, walltimestamp
is always 0, which together with the dmesg warnings seems to indicate
that it's not supported (yet).
# dtrace -qn 'syscall::exec*:return { printf(%Y
%s\n,timestamp,curpsinfo-pr_psargs); }'
1970 Jan 6 12:02:27 ping
1970 Jan 6 12:02:29 ls
1970 Jan 6 12:02:31 dtrace
Note that the timestamp value is relative to the time
the system is booted (I think), and not to midnight,
January 1, 1970.
Assuming your system has been running for a few days
and the offsets are right as well, the output seems fine.
At least on my system, timestamp offsets can only can be relied
on with either kern.timecounter.hardware=TSC or with C3
states disabled, though.
Measuring the elapsed time (in ms) between events that happen
in roughly 1 second intervals with kern.timecounter.hardware=HPET
and dev.cpu.0.cx_lowest=C2:
elapsed
value - Distribution - count
990 | 0
1000 |@@@ 57
1010 | 0
1020 | 0
1030 |@1
1040 | 0
elapsed avg1007
And doing the same with dev.cpu.0.cx_lowest=C3:
elapsed
value - Distribution - count
40 | 0
50 |@@@ 28
60 |@@@ 10
70 |@@@ 5
80 |@1
90 | 0
100 |@2
110 |@2
120 |@2
130 | 0
140 |@1
150 |@1
160 |@1
170 |@1
180 | 0
190 | 0
200 | 0
210 | 0
220 |@1
230 |@1
240 | 0
250 | 0
260 | 0
270 | 0
280 | 0
290 |@1
300 |@1
310 | 0
320 |@1
330 | 0
elapsed avg 90
Fabian
signature.asc
Description: PGP signature
dtrace walltimestamp
walltimestamp and timestamp don't appear to be right in BETA-1:
# dtrace -qn 'syscall::exec*:return { printf(%Y
%s\n,walltimestamp,curpsinfo-pr_psargs); }'
1970 Jan 1 10:00:00 date
1970 Jan 1 10:00:00 ping
1970 Jan 1 10:00:00 ls
# dtrace -qn 'syscall::exec*:return { printf(%Y
%s\n,timestamp,curpsinfo-pr_psargs); }'
1970 Jan 6 12:02:27 ping
1970 Jan 6 12:02:29 ls
1970 Jan 6 12:02:31 dtrace
dmesg:
dtrace_gethrestime(459): XXX
dtrace_gethrestime(459): XXX
dtrace_gethrestime(459): XXX
dtrace_gethrestime(459): XXX
dtrace_gethrestime(459): XXX
dtrace_gethrestime(459): XXX
dtrace_gethrestime(459): XXX
# date
Sun Aug 7 19:47:02 EST 2011
# uname -a
FreeBSD shikai 9.0-BETA1 FreeBSD 9.0-BETA1 #0: Tue Aug 2 09:35:34 EST 2011
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