tree 7b1787b1a32199354d1aaa61de8c2e0a0fd9204d
parent a9ebf6f422c1924b3c6486385babc38152c39500
author Elliott Hughes <enh@google.com> 1637287058 -0800
committer Elliott Hughes <enh@google.com> 1638831300 -0800

strftime: format small positive integers ourselves.

A decent chunk of the logcat profile is spent formatting the timestamps
for each line, and most of that time was going to snprintf(3). We should
find all the places that could benefit from a lighter-weight "format an
integer" and share something between them, but this is easy for now.

Before:

-----------------------------------------------------------
Benchmark                 Time             CPU   Iterations
-----------------------------------------------------------
BM_time_strftime        781 ns          775 ns       893102

After:

-----------------------------------------------------------
Benchmark                 Time             CPU   Iterations
-----------------------------------------------------------
BM_time_strftime        149 ns          147 ns      4750782

Much of the remaining time is in tzset() which seems unfortunate.

Test: treehugger
Change-Id: Ie0f7ee462ff1b1abea6f87d4a9a996d768e51056