Alexander Motin wrote:
Julian Elischer wrote:
In the Fusion-io driver we find that the limiting factor is not the
size of MAXPHYS, but the fact that we can not push more than
170k tps through geom. (in my test machine. I've seen more on some
beefier machines), but that is only a limit on small transacrtions,
or in the case of large transfers the DMA engine tops out before a
bigger MAXPHYS would make any difference.
Yes, GEOM is quite CPU-hungry on high request rates due to number of
context switches. But impact probably may be reduced from two sides: by
reducing overhead per request, or by reducing number of requests. Both
ways may give benefits.
If common opinion is not to touch defaults now - OK, agreed. (Note,
Scott, I have agreed :)) But returning to the original question, does
somebody knows real situation when increased MAXPHYS still causes
problems? At least to make it safe.
well I know we havn't tested our bsd driver yet with MAXPHYS > 128KB
at this time.. Must try that some time :-)
_______________________________________________
freebsd-current@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-current
To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
