Greetings,
Kris Kennaway wrote:
Stefan Lambrev wrote:
Hi,
Dag-Erling Smørgrav wrote:
Stefan Lambrev <[EMAIL PROTECTED]> writes:
I tested all different combination. The performance change is almost
invisible (100-200KB/s), and can't be compared with the performance
boost that TSC gain over ACPI-fast timecounter. Unfortunately TSC
doesn't play nice with power saving modes.
This will vary greatly from machine to machine, depending on the exact
hardware and the ACPI BIOS.
More modern machines have an HPET timer which is supposedly faster than
ACPI yet more reliable than TSC.
DES
I do not have HEPT on the servers that I test, but simple test on my
laptop shows
that hping can generate with ACPI-fast ~4MB/s traffic, 5MB/s with HPET
and 8MB/s with TSC. I didn't check dummy time counter.
Also I noticed that there is a kern.timecounter.tc.XXX.quality (read
only).
Can this be used to reduce quality and speed up performance?
No, they are meaningless values only used to rank the time counters
and choose one at boot.
You should use hwpmc to verify where the application is really
spending time, since gettimeofday doesn't seem to account for it all.
pmc: Unknown Intel CPU.
module_register_init: MOD_LOAD (hwpmc, 0xffffffff8029906d,
0xffffffff8054c500) error 78
What was the other way to do this profiling?
Can ktrace help?
Here is sample of kdump -R:
7501 hping 0.000013 RET sendto 40/0x28
7501 hping 0.000019 CALL sigaction(SIGALRM,0xbfbfe8a8,0xbfbfe890)
7501 hping 0.000014 RET sigaction 0
7501 hping 0.000013 CALL setitimer(0,0xbfbfe8b4,0xbfbfe8a4)
7501 hping 0.000016 RET setitimer 0
7501 hping 0.000017 CALL gettimeofday(0xbfbfe870,0)
7501 hping 0.000022 RET gettimeofday 0
7501 hping 0.000015 CALL gettimeofday(0xbfbfe868,0)
7501 hping 0.000016 RET gettimeofday 0
7501 hping 0.000015 CALL sendto(0x3,0x28317040,0x28,0,0x8067d80,0x10)
7501 hping 0.000026 GIO fd 3 wrote 40 bytes
--
Best Wishes,
Stefan Lambrev
ICQ# 24134177
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