Re: [PATCH] Timeouts gone wild on ia64

[Steve Dickson <SteveD@redhat.com>]

Trond Myklebust wrote:

>With a properly implemented algorithm, the number of retransmits
>should be small anyway as it is supposed to take into account the
>variance on the estimated RTO. We don't want any extra artificial
>limits if we can avoid it.
>
I totally greed... But this change, IMHO, will give a better estimated RTO
since all of the constants are based on the machine's HZ... At
least that's how I saw it...

>You may well be right in asserting that we're setting the initial RTO
>estimate too low, but then the answer should be to increase the value
>of the 'timeo' mount parameter as that is what defines the initial
>estimate.
>The default value of 'retrans' should also be looked at. I'm not at
>all comfortable with a default retrans value of '3' when doing soft
>mounts.
>
This was the direction I was headed until I saw the minimal RTO was
not HZ based... When I changed that which seem to take care of the
problem... I just stopped there... :(

>At the moment I believe that the default values for these 2 parameters
>differ in the kernel from those in the 'mount' program. IMHO, the
>mount program is overriding the kernel with too low values. It would
>be better if 'mount' did not set timeo/retrans (unless the user
>overrides) and left that to the kernel.
>
This definitely seems wrong....

SteveD.




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