Subject: Re: [linux-audio-dev] MCS: 64 bit timestamps?
From: Paul Barton-Davis (pbd_AT_Op.Net)
Date: su loka 10 1999 - 23:18:55 EDT
>So, 64 bit time and timestamps?
yes. even more significant given that the pentium cycle counter uses
such values, though many cycle counter users only read the low order
32 bits.
gcc is not to bad at dealing with "long long" arithmetic, either.
another word about timestamps though. you suggested that in order to
call engine->timestamp(), a sensor thread would have to preempt the
engine. Not true. more importantly, if every plugin/thread uses local
time, and that thread has no sample time base to clock from, how can
the engine ever convert events from that plugin/thread to its own time
base ?
this is where we need to go back to your suggestion of using the cycle
counter to determine the current sample number. its easy to do, and
provides very, very lightweight timing for any and everyone in the
system.
yes, it won't work on, say, a MIPS chip, but the alpha and all intel
chips have a cycle counter. don't know about the ultrasparc.
--p
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