I learned a lot from your discussion. Thanks. My question was from a network micro benchmark test which simulated OLTP workloads generating packet less than 200 bytes typically. And our result was only half of the x86's. It's easy to re-produce using uperf/netperf by sending huge amount of small packets.
We got papers on network performance tuning for both x86 Linux and POWER/AIX, the IRQ/CPU Affinity tuning are listed as a important option to boost numbers. And it is not mentioned in Linux on Z docs I can find. Anyway, it is good to know we are aware of this. all the best, James On Sat, Nov 18, 2017 at 8:01 PM, Sebastian Ott <[email protected]> wrote: > On Fri, 17 Nov 2017, Alan Altmark wrote: > > So what you're saying, Sebastian, is that (a) fine-grained control over > > what devices interrupt what CPUs is not in the Z architecture, (b) it's > > not in there for a good reason, (c) providing such a capability would > > adversely affect overall system performance (which is why it's not in the > > architecture in the first place). > > I've said (a) and gave my interpretation on why I don't think that this is > currently a huge issue. > > > It might, however, be an interesting idea to make the ioctl()s in the > > device driver a no-op instead of not being present or generating its own > > errnos. That way folks can turn the knob, feel better, but not see any > > change since "it doesn't get any better than this". > > Nope. That would be false advertising and an API violation. > > Sebastian > > ---------------------------------------------------------------------- > For LINUX-390 subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO LINUX-390 or > visit > http://www.marist.edu/htbin/wlvindex?LINUX-390 > ---------------------------------------------------------------------- > For more information on Linux on System z, visit > http://wiki.linuxvm.org/ > ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
