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RE: Meeting minutes 20060727
- From: "Stone, Joshua I" <joshua dot i dot stone at intel dot com>
- To: <jrs at us dot ibm dot com>, "Frank Ch. Eigler" <fche at redhat dot com>
- Cc: "Masami Hiramatsu" <masami dot hiramatsu dot pt at hitachi dot com>, <systemtap at sources dot redhat dot com>, "Mathieu Desnoyers" <mathieu dot desnoyers at polymtl dot ca>
- Date: Thu, 3 Aug 2006 13:05:33 -0700
- Subject: RE: Meeting minutes 20060727
On Thursday, August 03, 2006 12:43 PM, Jose R. Santos wrote:
> Frank Ch. Eigler wrote:
>> "Jose R. Santos" <jrs@us.ibm.com> writes:
>>
>>> [...] One of the things we are currently working on is to have an
>>> alternative to gettimeofday. [...]
>>
>> Josh Stone's kprobes-safe rendition gettimeofday has been in the
>> systemtap runtime for some time now. Is that not sufficient for
>> your purposes?
>>
>
> The goal here is to improve performance. Gui Jian has timed
> _stp_gettimeofday_us() using LKET and it give a bigger overhead than
> do_gettimeofday(). By doing this in user space we can obtain better
> performance by avoiding disabling preemption or calling seqlock like
> _stp_gettimeofday does.
If you have suggestions for improving _stp_gettimeofday, I'm all ears.
I'm never of the mind that the existing code is the perfect solution.
But then, if you're doing something from userspace, I guess I don't
fully understand your usage model, or how that will be faster...
Josh