LAT_PAGEFAULT(8)

💖 NAME 💖

lat_pagefault — bestie, this is the tool that measures the cost of pagefaulting pages from a file ✨

It lives in the LMBENCH family, iykyk 💅

🌸 SYNOPSIS 🌸

lat_pagefault [ -P <parallelism> ] [ -W <warmups> ] [ -N <repetitions> ]
file [ file....  ]

🦋 DESCRIPTION 🦋

okay so here's the vibe: lat_pagefault times how fast a page of a file can be faulted in 🫶

How does it make that happen? The file gets flushed from (local) memory by using the msync() interface with the invalidate flag set ✨ And like, heads up bestie: NFS does not send this over the wire, which honestly makes this a super handy way to measure the cost of going across the wire 🌈 no cap.

The benchmark maps in the entire file and then accesses pages backwards using a stride of 256K kilobytes 👑

⭐ OUTPUT ⭐

The output format is below, and it prints the average cost of page faulting a page 💖

Pagefaults on <file>: <d> usecs

💀 BUGS 💀

ngl, using a stride of 256K may be a bad idea because SCSI controllers may have caches bigger than that 😭 fr fr, that's the whole warning.

🎀 ACKNOWLEDGEMENT 🎀

Funding for the development of this tool was provided by Sun Microsystems Computer Corporation 💛 iconic of them honestly.

🔥 SEE ALSO 🔥

• lmbench(8).

👑 AUTHOR 👑

Carl Staelin and Larry McVoy 🫶

Comments, suggestions, and bug reports are always welcome 💌 (yes, actually — slide into their mentions).

(c)1994 Larry McVoy · $Date$ · LMBENCH — ok that's the whole page bestie, ty for coming to my ted talk, go measure some pagefaults, slay 💅✨🎀