Messages in this thread | | | Date | Fri, 3 Aug 2018 10:32:52 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH 1/3] perf auxtrace: Support for perf report -D for s390 |
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Em Fri, Aug 03, 2018 at 12:07:58PM +0200, Hendrik Brueckner escreveu: > Arnaldo, > > On Thu, Aug 02, 2018 at 09:49:09AM -0300, Arnaldo Carvalho de Melo wrote: > > Em Thu, Aug 02, 2018 at 09:46:20AM +0200, Thomas Richter escreveu: > > > Add initial support for s390 auxiliary traces using the > > > CPU-Measurement Sampling Facility. > > > > Could you please provide one or two paragraphs explaining what is this > > "CPU-Measurement Sampling Facility", in which hardware this is available > > (all s/390 hardware has it? Just the 64-bit model(s)?) and provide a > > public URL for people interested in further reading? > > The CPU-Measurement Facility (CPU-MF) provides a set of functions to obtain > performance information on the mainframe. Basically, it was introduced > with System z10 years ago for the z/Architecture, that means, 64-bit. > For Linux, there are two facilities of interest, counter facility and sampling > facility. The counter facility provides hardware counters for instructions, > cycles, crypto-activities, and many more. > > The sampling facility is a hardware sampler that when started will write > samples at a particular interval into a sampling buffer. At some point, > for example, if a sample block is full, it generates an interrupt to collect > samples (while the sampler continues to run). > > Few years ago, I started to provide the a perf PMU to use the counter > and sampling facilities. Recently, the device driver was updated to also > "export" the sampling buffer into the AUX area. Thomas now completed the > related perf work to interpret and process these AUX data. > > If people are more interested in the sampling facility, they can have a > look into: > > - The Load-Program-Parameter and the CPU-Measurement Facilities, SA23-2260-05 > http://www-01.ibm.com/support/docview.wss?uid=isg26fcd1cc32246f4c8852574ce0044734a > > and to learn how-to use it for Linux on Z, have look at chapter 54, > "Using the CPU-measurement facilities" in the: > > - Device Drivers, Features, and Commands, SC33-8411-34 > http://public.dhe.ibm.com/software/dw/linux390/docu/l416dd34.pdf
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Thanks a lot, I added this to the first commit, people investigating this should be able to find that when doing research about the implementation details.
- Arnaldo
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