* Front end: draw the capsule wall without clipping it every frame
The tilted wall clipped each capsule to a rounded rect and recomposed its columns on every drift
step, and a rotated rounded clip is rasterised in software on the render threads: the idle main
page held about 1.7 cores. The art is now loaded at the capsule's size with its corners already
rounded, each column draws its capsules itself in one layer moved by the drift, and the drift
advances at most every 15 ms. The idle page takes about a third of a core.
* libfakeinput: let calls on descriptors it does not serve skip its lock
Every read, write, ioctl, close and poll of every process in a Proton session went through the
controller lock and the three map lookups, Wine's wineserver pipes and the game's files alike.
A bitmap of the descriptors the maps hold, set before one is handed out and cleared when it is
closed, lets everything else go straight to the kernel.
* Pad motion: ask the display for its rotation four times a second
The rotation was looked up for every sensor reading, every 2 ms, and cost more than the rest of
the reading; it is now refreshed every 250 ms, and the readings no longer allocate pairs.
* Session: keep the library passes out of a game's launch
The redist seeder stamped each prefix with the checksum of the whole set of names, which differs
between the session's pass and the game launch's (the game's own names are added), so every
launch re-appended the markers to every prefix in the library while the game loaded. Each
prefix's marker now lists the names it was given and only the missing ones are added.
The beat's seed and compatibility passes, and the Lossless Scaling ownership probe (which loads
steamclient.so), also wait while a wineserver runs: a launch rewrites the manifest and made them
due at exactly that moment. The game's own launch seeds its prefix regardless.
* Agent: keep the focus watcher's X connection open while nothing changes
The connect timeout stayed on the socket, so with no property change the read timed out, and the
watcher dropped the connection, reconnected and took a fresh snapshot every few seconds.
* Game environment: start Cyberpunk 2077 without REDlauncher
The prelauncher opens REDlauncher, a Qt WebEngine window that hands over to the game half a
minute later and then stays up beside it, well over a core busy for as long as the game runs; its
own --launcher-skip started the game twice. The game's executable is started directly instead.
* netif: answer Wine's network driver from a reading of the link
Mortal Kombat X has Wine's network driver enumerate every interface, address and route table
hundreds of times a second. Each enumeration read /etc/droiddeck-net several times, asked the
kernel for its interface dump again (a netlink socket bound under proot, refused each time) and
looked the real functions up with dlsym. The link file is now read at most once a second, a
refused dump is not asked for again within that second, and the real functions are looked up
once.
* Fast path: create memfds without a stop in proot
proot looks at a memfd's name only to refuse the few that are then executed or locked; every other
memfd_create is now issued from the trampoline. The session's /proc/net and status copies made
one per read, a stop each. Without memfd in the kernel the call still goes to proot's ashmem.
* Logs: run each redaction rule only on a line that could match it
A session's end copies some 70 MB of the Steam client's logs and puts every line through all
twenty-odd rules, most of a minute of a core on the phone after every session. Each rule now runs
only on a line holding what it cannot match without: its keyword, the five separators of a MAC,
the four dashes of a GUID, a long enough hex or token run, the learned account or address text.
Lines with non-ASCII text still meet every case-insensitive rule. Over 895,000 lines of real
client logs, with the device's accounts and addresses learned, the output is identical and the
pass takes a twentieth of the time.
* perf: fast path resolves links, /proc and glue as proot does, and answers uname, isatty and passwd
The fast path handed back to proot whatever crossed a symlink, /proc or a directory proot
only shows as glue, which is most of what Steam and Wine ask. It now walks a path the way
proot's canonicalize() does, so those calls stay in-process:
- links are followed in guest terms and their text detranslated as detranslate_path() does,
including readlink into a buffer the kernel cut short and /proc's exe, cwd and fd links;
- a binding proot dropped at start is dropped here too, glue above a binding is ENOENT, and a
last component proot cannot stat is left to the kernel;
- pipe and socket dirfds are ENOTDIR, rmdir("dir/") removes dir, and "." and ".." go to proot;
- a blocking accept() with a connection already waiting no longer goes to proot.
Also answered: uname() and gethostname() (proot's utsname never changes), isatty() (glibc
2.43 asks with TCGETS2, which proot rewrites) and getpwnam/getpwuid when nsswitch.conf
sends passwd to files first and the entry is there (Xwayland asks for every client).
equiv.py, equiv2.py and equiv3.py match line for line with and without the fast path
(222, 507 and 924 lines). Per call on the RedMagic: realpath 240 us -> 1.0 us,
realpath /proc/self/fd/N 408 -> 9.9, getpwuid 41.5 -> 4.6, uname 28 -> 0.006.
* perf: LD_AUDIT module skips library lookups proot would fail
ld.so looks each library up along the game's search path, and Proton puts the game's
directory, Steam's runtime and video directories and its own library directories ahead of
/usr/lib: 72% of ld.so's opens in an Among Us launch failed, each a round trip to proot.
libblaudit.so answers la_objsearch() for a candidate proot would certainly fail with ENOENT
(its directory walked as canonicalize() walks it, the name or a directory on the way missing).
It has no libc and maps the fast path's trampoline itself. Each lookup's first candidate is
still opened, since a skipped one fails with ld.so's errno as it stands, and the default
directories are never skipped, so dlerror() reads the same. droiddeck-proton and the extra
wrapper add it to LD_AUDIT when the fast path is on.
* perf: droiddeck-proton checks a tool's components with one sha256sum
Each program the launcher starts pays a dozen traced library lookups under the game's search
path before it does anything. One sha256sum over every listed file replaces one per file;
the check itself is unchanged.
* perf: build a locale archive for C.UTF-8
Every program loads the locale LANG names before main(). glibc ships C.UTF-8 as a directory
it looks for once per category under two spellings, before reading gconv's module lists:
about 30 opens, each a stop in proot, in every process of the session. droiddeck-session
builds /usr/lib/locale/locale-archive (and gconv's cache) once per glibc package, so that is
one open.
localedef names a finished archive by hard link, which Android refuses; with
DROIDDECK_LINK_RENAME=1 libblsession turns a refused link into a rename that will not replace
an existing name.
* perf: library beat starts its helpers only when what they read changed
Every 15 s the session ran droiddeck-seed-redists (some forty programs under proot) and, when
a library directory had changed, steam-compatibility: a burst of thousands of proot stops each
quarter minute, game loads included. The seeder now runs when a library changed or a prefix
(or Proton's template for them) is unmarked, the compat pass when a manifest, depot, tool or
config.vdf changed, both checked from bash without starting anything, and each every five
minutes regardless. The seeder reads its stamp and the time without a subshell each.
* perf: fakeinput opens pad.log on its first line
Every process the library is loaded in opened the session's pad.log at start, a stop in proot
on shared storage, and most never write to it. The file is now opened when there is a line to
write.
* docs: the fast path as it ships, the audit module and measured launch times
* fix: a game the app launches after an idle spell comes to the front
The Steam client brings a game it launched forward only while it counts someone as present,
which it reads from gamescope's input counter. A game the app launched after four or more
minutes without a touch started, mapped its window, and stayed behind the library page until
the next input (device: Palworld, Stardew Valley, Fallout: New Vegas, Mortal Kombat X; the same
on main). The session now watches a requested launch, and when the game's window is focusable
but the interface keeps focus for two polls, counts one input on gamescope's counter, as a key
would. Nothing changes for a launch the client already brings forward.
* Fast path: hold every bind, so added games start in their own folder
libblfastpath kept the first 64 binds and dropped the rest without a word. A session has 87 (two
Games folders are the last two), so /root/Games/<folder>/... was mapped into the rootfs - the
empty mount point - instead of the bound storage. Wine resolves a new process's working directory
by those paths, found no drive for it and started every added game in C:\windows ("could not
find DOS drive for current working directory"): DiRT 3 did not mind, FEZ looks for
Content\Essentials.pak there and quits.
The library now holds 256, and turns itself off for the process when a bind does not fit or the
list runs past that, leaving the call to proot, which never maps it wrong. The app keeps the fast
path off for a session with more binds than that.
Verified on an AYANEO Pocket FIT: FEZ (added game) reaches its title screen; the warning is gone.
* Fast path: say in the session log when it stays off
---------
Co-authored-by: The412Banner <the412banner@users.noreply.github.com>
Preload library answers stat/open/access/readlink in-process via a
trampoline page proot 0014 lets through seccomp. On by default with a
Performance toggle; also sets GLIBC_TUNABLES rseq=0 and malloc top_pad.
MaxsTechReview