Subject: Re: Linux: the next step

From: Steve Alexander <[email-masked]>
Date: Mon, 12 Aug 1996 14:18:18 -0700

Bob English <renglish@ratliff> writes:
>If you look at larry's context switch and pipe benchmarks, you'll see
>that they run much faster on a single CPU than on two or more.  A lot of
>the difference is due to fine-grained locking, which causes more dirty
>cache lines to thrash than is actually necessary for the operations
>involved.  Pipe communication takes locks at the vnode and inode
>level.  Context switches take locks on threads, accounting structures,
>and queues.

If I look at those benchmarks, they'll probably run faster on Linux on an Indy
than they do on IRIX on an Indy, so I doubt the locking is the big problem we
need to be looking at.  I don't have numbers from David to quote, so maybe I'm
wrong.  I'd like to be wrong.

-- Steve

---

From: Bob English <[email-masked]>
Date: Mon, 12 Aug 96 14:24:15 -0700

>wrong.  I'd like to be wrong.

I was comparing Irix MP times vs. Irix UP times, and the difference is
both substantial and locking related.  Of course, if Irix were as
efficient on a UP as Linux, the difference might be a factor of 10
rather than a factor of 2 :-).

--bob--