[mvapich-discuss] Send Work Queue

Tue Mar 4 05:58:08 EST 2008

Hi Lei ,

thanks for useful information; I've browse through the code but i found there is checking 

for mrail.send_wqes_avail[] variable ( which is set to 280 default ) before posting any buffer  everytime . . .

if this check is there, then when mvapich going to post credit information ? (without checking above variable) 
so it will use reserved 20 slots.

Waiting for reply,
thanking,
Nilesh

----- Original Message ----
From: LEI CHAI <chai.15 at osu.edu>
To: nilesh awate <nilesh_awate at yahoo.com>
Cc: MVAPICH2 <mvapich-discuss at cse.ohio-state.edu>
Sent: Friday, 29 February, 2008 12:42:08 AM
Subject: Re: [mvapich-discuss] Send Work Queue

Hi Nilesh,

THe 20 WQE's are reserved for credit information. It's true that it only works for netowrks that provides more than 20 WQE's, and so far we have not encountered a network that provides less than 20 WQE's. We will revise it in the future.

Lei

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=0AHi all, =0A=0AI'm using mvapich2 1.0.1over ofed 1.2(udapl stack) =0A=0AI=
n mvapich source code(udapl/rdma_udpl_prive.c) i've observed foll. thing=0A=
=0Avc->mrail.send_wqes_avail[i] =3D rdma_default_max_wqe - 20;=0A=0Ardma_de=
fualt max_wqe which is 300 default=0A=0Abut if some provder have ep_attr.ma=
x_request_dtos =3D 16(for an example);  then we need to set=0A=0Aan env MV2=
_DEFAULT_MAX_WQE(which is not given in user guide) to 36(to get exaclty 16 =
) as per the above code line=0A=0ASo please some one explain the significan=
ce subtracting "20" from default work queue size.=0A=0Aor is it reserving(2=
0 slot) kind of thing  ? (if it is so then provider with 16 dtos will be in=
 trouble)=0A=0AWating for reply=0A=0ANilesh.=0A=0A =0A=0A=0A=0A=0A=0A=0A   =
   Unlimited freedom, unlimited storage. Get it now, on http://help.yahoo.c=
om/l/in/yahoo/mail/yahoomail/tools/tools-08.html/
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<html><head><style type=3D"text/css"><!-- DIV {margin:0px;} --></style></he=
ad><body><div style=3D"font-family:times new roman, new york, times, serif;=
font-size:12pt"><br><div>Hi all, <br><br>I'm using mvapich2 1.0.1over ofed =
1.2(udapl stack) <br><br>In mvapich source code(udapl/rdma_udpl_prive.c) i'=
ve observed foll. thing<br><br><span style=3D"font-weight: bold; color: rgb=
(64, 160, 255);"><span style=3D"color: rgb(0, 128, 255);"></span><span styl=
e=3D"color: rgb(0, 128, 255);"></span></span>vc-&gt;mrail.send_wqes_avail[i=
] =3D rdma_default_max_wqe - 20;<br><br>rdma_defualt max_wqe which is 300 d=
efault<br><br>but if some provder have ep_attr.max_request_dtos =3D 16(for =
an example);&nbsp; then we need to set<br><br>an env MV2_DEFAULT_MAX_WQE(wh=
ich is not given in user guide) to 36(to get exaclty 16 ) as per the above =
code line<br><br>So please some one explain the significance subtracting "2=
0" from default work queue size.<br><br>or is it reserving(20 slot) kind of
 thing&nbsp; ? (if it is so then provider with 16 dtos will be in trouble)<=
br><br>Wating for reply<br><br>Nilesh.<br><br>&nbsp;</div><span style=3D"fo=
nt-weight: bold; color: rgb(64, 160, 255);"><span style=3D"color: rgb(0, 12=
8, 255);"><br></span></span><div><br></div></div><br>=0A=0A=0A      <!--2--=
><hr size=3D1></hr> Did you know? You can CHAT without downloading messenge=
r. <a href=3D"http://in.rd.yahoo.com/tagline_webmessenger_2/*http://in.mess=
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