From de0fe1b7b926233ddb03d6fd136b62f6f7295b44 Mon Sep 17 00:00:00 2001 From: Ben Pfaff Date: Tue, 20 Dec 2005 18:35:50 +0000 Subject: [PATCH] Clarify that adding code where interrupts are already disabled may be necessary. --- doc/threads.texi | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/doc/threads.texi b/doc/threads.texi index 28b87fa..6b93dbb 100644 --- a/doc/threads.texi +++ b/doc/threads.texi @@ -328,9 +328,14 @@ timer ticks or input events. Turning off interrupts also increases the interrupt handling latency, which can make a machine feel sluggish if taken too far. +You may need to add or modify code where interrupts are already +disabled, such as in @func{sema_up} or @func{sema_down}. You should +still try to keep this code as short as you can. + Disabling interrupts can be useful for debugging, if you want to make sure that a section of code is not interrupted. You should remove -debugging code before turning in your project. +debugging code before turning in your project. (Don't just comment it +out, because that can make the code difficult to read.) There should be no busy waiting in your submission. A tight loop that calls @func{thread_yield} is one form of busy waiting. -- 2.30.2