- Deal with __android_log_is_loggable inside signal handler by
treating a lock contention system call as more costly than reading
the associated property directly. Rather waiting around in a
contended stat to hit cache.
- Check both the individual known __system_property_serial() and
global __system_property_area_serial() to detect updates or
additions to the properties to respond in the most aggressive and
timely manner. __android_log_is_loggable() return at max CPU
clockrate on a N9 in 61ns.
- Craft a common do_cache2 inline that adds the above to the other
functions that utilize cache handling and preserves (within 3ns)
performance in android_log_clockid() and __android_log_security().
These functions return at max CPU clockrate on a N9 in 23ns.
Bug: 19544788
Bug: 25693940
Bug: 25792367
Bug: 26178938
Change-Id: I9cd94598f5c558e946b93977ad3714a4b03d0422
This test tells us that scatter-gather (writev instead of write)
carries a small ~2% penalty. Unaligned buffer carry a similar
additional penalty. On N9 it takes 3us to 22us _just_ to write
the pmsg logs, depending on size. Some assumptions about the
socket read and write performance for the main logging can be made
from tracking these results and should improve design decisions.
Bug: 18771697
Bug: 23685592
Change-Id: Id4d64c449140e4f39078c62b0097e403df91fe0c
- On a N9 64-bit benchmark, the __android_log_is_loggable overhead
is roughly 500ns (1/2 of a syscall?)
Bug: 19544788
Bug: 17760225
Bug: 20416721
Change-Id: Ib9e4d06d96e1b19ca5d459e569ead451ef47a9c0
Move away from using POSIX open(2) flags and introduce ANDROID_LOG_* flags to
replace them. Add security by preventing random mode flags from getting into
underlying POSIX calls. ANDROID_LOG_* flags overlap POSIX O_* flag definitions.
Change-Id: Ib32bb64c287e8bf150be62242e1ba46bb37839fc
- structure packing
- move towards log_time from struct timespec
- extend log_time to cover differences between
log_time and struct timespec
Change-Id: I106ed0b609917306d170044054b5b32645f2a295
Mark Salyzyn