Subject: Re: SYSCALL_DEBUG and latency...
To: None <email@example.com, firstname.lastname@example.org>
From: Toru Nishimura <email@example.com>
Date: 02/16/2001 10:06:02
> I've just done several tests on my Magnum, based on the odd behavior that
> enabling SYSCALL_DEBUG typically allows a successful boot to a single-user
> shell. Testing the theory of introduced latency, I've inserted DELAY calls
> as high as 1 second where scdebug_call and scdebug_ret would be called from
> arch/mips/mips/syscall.c. The tests were unsuccessful. It would seem the
> sheer latency introduced by SYSCALL_DEBUG does not account for the successful
> booting. It may prove to be more of a memory issue than one of timing.
> It's hard to say right now.
Cache issue? Inserting SYSCALL_DEBUG code paths alters and bumps out
(stale) cache entries in effect. Can you see any good/poor behaviour
difference to force R4000 to have write-thru pages?
#define MIPS3_PG_CACHED 0x0