[openib-general] Re: FW: SDP problems with 64K page size

[Jerome Pioux]

> The best way to fix this appears to be to bump the counters up to u32 or 
> s32.

Just an open question: Do you think that we could get better performance if 
we would go with u32 instead of reducing the buffer to 16K?

Jerome


----- Original Message ----- 
From: "Michael S. Tsirkin" <mst at mellanox.co.il>
To: "Roland Dreier" <rolandd at cisco.com>; "Tom Duffy" 
<thomas.duffy.99 at alumni.brown.edu>; "Jerome Pioux" <jerome.pioux at bull.com>
Cc: <openib-general at openib.org>
Sent: Sunday, September 25, 2005 3:45 AM
Subject: Re: FW: SDP problems with 64K page size


> Quoting r. Roland Dreier <rolandd at cisco.com>:
>> Subject: FW: SDP problems with 64K page size
>>
>> Hi, Jerome asked me to forward this on, since for some reason his
>> email didn't appear when he sent it.
>>
>> In any case there seem to be some PAGE_SIZE dependencies in SDP.
>> Libor provided a patch that fixed this up a while ago, but I don't
>> know if this is the right way to handle this.
>>
>>  - R.
>
> Roland, thanks very much for forwarding this, and for providing
> a patch to Jerome.
>
> The problem is with recv_size/send_size counters in SDP, which are u16,
> so that assigning a value of 64K overflows them.
> The best way to fix this appears to be to bump the counters up to u32 or 
> s32.
> The patch that Roland posted fixes this by reducing the buffer
> size to 16K, so that should work, too.
>
> Roland, I might check in the patch that you posted to work around
> this problem for 64K page users, until I have a final fix ready.
> Is that OK with everyone?
>
> Thanks,
>
> -- 
> MST