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runtime: don't print debug messages to the UART. 

It takes ~4ms to print an empty log line because of how slow
the UART is. This makes the log timestamps useless for debugging
performance problems.

After this commit, it takes ~75us to print an empty log line instead,
which pessimizes test_rpc_timing by less than 2ms with tracing
enabled.
This commit is contained in:
whitequark 2016-11-12 20:16:25 +00:00
parent acc5e53b32
commit 3ce1826891
2 changed files with 6 additions and 4 deletions
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2
artiq/runtime.rs/src/lib.rs
View File

@ -97,7 +97,7 @@ pub extern "C" fn _Unwind_Resume() -> ! {
#[no_mangle] #[no_mangle]
pub unsafe extern fn rust_main() { pub unsafe extern fn rust_main() {
static mut LOG_BUFFER: [u8; 4096] = [0; 4096]; static mut LOG_BUFFER: [u8; 65536] = [0; 65536];
BufferLogger::new(&mut LOG_BUFFER[..]) BufferLogger::new(&mut LOG_BUFFER[..])
.register(move || { .register(move || {
info!("booting ARTIQ..."); info!("booting ARTIQ...");

4
artiq/runtime.rs/src/logger.rs
View File

@ -1,6 +1,6 @@
use core::{mem, ptr}; use core::{mem, ptr};
use core::cell::RefCell; use core::cell::RefCell;
use log::{self, Log, LogMetadata, LogRecord, LogLevelFilter}; use log::{self, Log, LogLevel, LogMetadata, LogRecord, LogLevelFilter};
use log_buffer::LogBuffer; use log_buffer::LogBuffer;
use clock; use clock;
@ -61,8 +61,10 @@ impl Log for BufferLogger {
writeln!(self.buffer.borrow_mut(), writeln!(self.buffer.borrow_mut(),
"[{:12}us] {:>5}({}): {}", "[{:12}us] {:>5}({}): {}",
clock::get_us(), record.level(), record.target(), record.args()).unwrap(); clock::get_us(), record.level(), record.target(), record.args()).unwrap();
if record.level() <= LogLevel::Info {
println!("[{:12}us] {:>5}({}): {}", println!("[{:12}us] {:>5}({}): {}",
clock::get_us(), record.level(), record.target(), record.args()); clock::get_us(), record.level(), record.target(), record.args());
} }
} }
}
} }