gcc and alphalinux

[David Addison]

I just recompiled our comms libs and MPICH (1.2.0) using ccc with flags '-fast
-O4' and it did wonders for my bandwidth! For some message sizes we now get
30MB/s more than with gcc (egcs-2.91.66). Here are revised Pallas EFF_BW
numbers for a pair of API 2 * 667MHz UP2000 nodes running RH6.1 (2.2.15
kernel)


***********************************************************

Running on 2 PEs

sampling from 2^0 to 2^20  bytes

Effective Bandwidth:  95.70 [MB/sec]


***********************************************************

(The PingPong latency is 4.88 usec for 0 byte messages. And the peak bandwidth
for 1 MB messages is 211 MB/s)

The previous figure I posted was 84.91 [MB/sec]  - this new figure is much
closer to that achieved on the Tru64 platforms.


Thanks Compaq! (Sorry the figures are for an API box, but I'm sure a DS20
would be just as good ;-)


Addy.

-----Original Message-----

> From: John Burton [mailto:j.c.burton at gats-inc.com]
> Sent: Thursday, May 25, 2000 4:24 PM
> To: Tenhave, Tim
> Cc: 'Mathew Lee'; beowulf at beowulf.org
> Subject: Re: gcc and alphalinux
>
> Just out of curiousity, has anyone used the Compaq Alpha compilers for
> Linux, and if so how do they compare with gcc, and Ture Unix64. I'm
> currently setting up an ev-6 Alpha based cluster for some Atmospheric
> Radiance codes and would like to know which way I should go...
>
> John
>
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