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Re: [PATCH] kprobes for s390 architecture
- From: fche at redhat dot com (Frank Ch. Eigler)
- To: Mike Grundy <grundym at us dot ibm dot com>
- Cc: Heiko Carstens <heiko dot carstens at de dot ibm dot com>, Martin Schwidefsky <schwidefsky at de dot ibm dot com>, Jan Glauber <jan dot glauber at de dot ibm dot com>, systemtap at sources dot redhat dot com, dwilder at us dot ibm dot com
- Date: 10 Jul 2006 10:25:11 -0400
- Subject: Re: [PATCH] kprobes for s390 architecture
- References: <20060623150344.GL9446@osiris.boeblingen.de.ibm.com> <OF44DB398C.F7A51098-ON88257196.007CD277-88257196.007DC8F0@us.ibm.com> <20060623222106.GA25410@osiris.ibm.com> <20060624113641.GB10403@osiris.ibm.com> <1151421789.5390.65.camel@localhost> <20060628055857.GA9452@osiris.boeblingen.de.ibm.com> <20060707172333.GA12068@localhost.localdomain> <20060707172555.GA10452@osiris.ibm.com> <20060708185428.GA26129@localhost.localdomain>
grundym wrote:
> > How fast is this if you have to exchange several hundred instructions?
>
> I'll have to do some timing tests to measure how much overhead it
> puts on the system. It's a trade off of safety vs speed. [...]
No question, safety has to be paramount.
> The plus side is the swaps are only done on activation and
> deactivation, and don't have this kind of overhead during
> operations. [...]
Even though infrequent, we should nevertheless measure
activation/deactivation times, since it is not hard to insert and
remove thousands of kprobes in a single script. If those times are on
the order of milliseconds, and if batching them into one operation can
allow sharing of synchronization overhead, then we will need to adopt
that.
- FChE