Remote socket RFOs will result in a directory update which, in turn, will cause a write command.”

IMC_WRITES_COUNT includes: “NOTE: Directory bits are stored in memory.

CHA Events “DIR_LOOKUP” and “DIR_UPDATE”.

Specific references in this manual include: The version that I have spent the most time with is for the 1st and 2nd generations of Intel Xeon Scalable Processors (“Skylake Xeon” and “Cascade Lake Xeon”): “Intel® Xeon® Processor Scalable Memory Family Uncore Performance Monitoring Reference Manual”, Intel document 336274. Much of the detailed understanding of the memory directory implementation comes from studying the uncore performance counter events that make reference to memory directories.Īs an example, there are direct references to memory directories in several sections of the Intel Uncore Performance Monitoring Guides for their various processor families.

(I apologize in advance if the links are broken - it is hard to keep up with web site reorganizations - but the presentations should be relatively easy to find using web search services.) Implicit Information: The Intel Hot Chips presentation on Ivy Bridge EP describes the memory directory feature and says that it was upgraded from one bit to two bits in the IVB-EP processor – describing the 3 states that are still used.The Intel Hot Chips presentation on Westmere-EX describes an early implementation of the memory directory (slides 9-12):.Intel has disclosed various details in some presentation at the Hot Chips series of conferences: The language is not as precise as I would prefer, but there are actually quite a few interesting details in that section. The clearest admission that the memory directory feature exists is in this “technical overview” presentation – in the section “Directory-Based Coherency” –. That was boring, so I am posting my notes here so I can find them again - maybe others will find this useful as well…. When asked for references to public information about the Intel’s memory directory implementation, I had to go back and find the various tiny bits of information scattered around different places. “A Memory Directory is one or more bits per cache line in DRAM that tell the processor whether another socket might have a dirty copy of the cache line.” I have referred to this in various presentations as: This is used in multi-socket systems to reduce cache coherence traffic between sockets. Once you switch this option on, your logon screen will always match your wallpaper, giving the system a uniform look.Īs far as wallpaper switchers go, John’s Background Switcher is one of the most capable tools I’ve had the pleasure of using so far, and it comes at a price that can’t be beat.One of the (many) minimally documented features of recent Intel processor implementations is the “memory directory”. John (the developer) tells me this was accomplished by having the installer tweak file permissions, making prompts unnecessary. JBS makes the switch seamless, nary a prompt in sight. This is not the first utility I’ve come across that can do this: Commercial tool DisplayFusion Pro also includes an option to replace the logon screen background, but pops up a UAC prompt every time it tries to switch backgrounds. JBS can also change the background for the Windows logon screen.

This way, you don’t lose all the time you spent configuring it, and can enable it at a later time. On the other hand, if it is working but you’re just tired of it for now, you can just disable that feed in JBS.

If an entire source isn’t returning the results you’d hoped for, you can always tweak it and try again. If you like a certain feed but find an image offensive, you can right-click the JBS system tray icon and select “Never Show Again.” JBS saves its URL in a “banned wallpapers” list, and that’s the last time you’re likely to see of that particular wallpaper. Since images are pulled off the wild wild Web, they may not always agree with you.

Johns background switcher cache too big