I read the article. This article is about transactional event facility introduced in z/EC-12 and not PLO which is an LL/CS. I wish I had access to a z/EC-12 with the transactional event facility to play with it and compare it to PLO. The transactional event facility is much more comprehensive and not as granular as a PLO. In PLO, the hardware locking occurs according to the lock word.
I've done a lot of testing with PLO. It can increase CPU, particularly in a situation where updates are much higher percentage of the operations. But in all applications that I've tested, it's CPU overhead is offset by higher throughput. In a traditional locking method, tasks end up serializing to the lock. Kenneth -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of David Crayford Sent: Sunday, November 10, 2013 6:50 PM To: [email protected] Subject: Re: Serialization without Enque On 11/11/2013 5:19 AM, Mark Zelden wrote: > On Sat, 9 Nov 2013 19:47:35 GMT, [email protected] <[email protected]> wrote: > >> I have been reading and following this thread sine PLO is not an instruction >> I use every day. >> It would be nice if someone would actually post some working code using a >> PLO instruction, to illustrate how one would add an element to a queue and >> remove an element from a queue. >> >> Paul D'Angelo > I've not been paying that close of attention, but I'm more curious > about what people did for these situations prior to PLO. They used smart algorithms using the atomic instructions they had, like RCU http://en.wikipedia.org/wiki/Read-copy-update. It's interesting that I have never seen any use of the PLO instruction in the zLinux kernel code. Paul McKenney, IBMs expert on these things, wrote a good article that suggests that Hardware Transaction Memory may not be the panacea we all expect it to be, and in some cases may actually increase CPU http://paulmck.livejournal.com/31285.html. > Mark > -- > Mark Zelden - Zelden Consulting Services - z/OS, OS/390 and MVS > mailto:[email protected] ITIL v3 Foundation Certified Mark's MVS > Utilities: http://www.mzelden.com/mvsutil.html > Systems Programming expert at > http://search390.techtarget.com/ateExperts/ > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, send > email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
