SV: iscsi initiator speed very low in FreeBSD 7

[Thomas Steen Rasmussen]

Hello

The patch works! :) I had some problems getting it to apply cleanly,
due to a (junk?) character in the source file (the file being patched) line 456.
Once I got it applied to a fresh 7 install the speed was considerably better.
In my test setup I got to around 20 megabytes / sec to or from my laptop initiator.
I now need to test the production server with the actual appliance SAN,
and see what kind of speeds I get there. I will revert with the results here.

Until then, thank you very much for your assistance.

Med venlig hilsen / Kind regards

Thomas Steen Rasmussen
Sikkerheds- & Unix-administrator
Siminn

-----Oprindelig meddelelse-----
Fra: owner-freebsd-scsi at freebsd.org [mailto:owner-freebsd-scsi at freebsd.org] På vegne af Pierre Beyssac
Sendt: 27. februar 2008 13:51
Til: Ivan Voras
Cc: freebsd-scsi at freebsd.org
Emne: Re: iscsi initiator speed very low in FreeBSD 7

On Wed, Feb 27, 2008 at 01:45:35PM +0100, Ivan Voras wrote:
> > Better with the patch... :-)
> I think you need to send a file with a .txt extension for it to pass the
> spam / list filters.

Here it is inline...

--- isc_sm.c    2007-07-24 17:35:02.000000000 +0200
+++ /tmp/isc_sm.c       2008-02-26 16:53:54.000000000 +0100
@@ -325,7 +325,9 @@
          mtx_unlock(&sp->io_mtx);      // XXX
      }
 #else
+     mtx_lock(&sp->io_mtx);    // XXX
      wakeup(&sp->flags);
+     mtx_unlock(&sp->io_mtx);  // XXX
 #endif
      return error;
 }
@@ -454,6 +456,11 @@
      }
 }

+/*
+ * Should be called with sp->io_mtx held to avoid race condition
+ * on queue empty.
+ * Returns with sp->io_mtx held.
+ */
 static int
 proc_out(isc_session_t *sp)
 {
@@ -481,6 +488,8 @@
          if((pq = i_dqueue_snd(sp, which)) == NULL)
               break;

+         mtx_unlock(&sp->io_mtx);
+
          pp = &pq->pdu;
          bhs = &pp->ipdu.bhs;
          switch(bhs->opcode) {
@@ -523,6 +532,8 @@
               xdebug("error=%d ndone=%d opcode=0x%x ccb=%p itt=%x",
                      error, ndone, bhs->opcode, pq->ccb, ntohl(bhs->itt));
               if(error == EPIPE) {
+                   pdu_free(sp->isc, pq);
+                   mtx_lock(&sp->io_mtx);
                    // XXX: better do some error recovery ...
                    break;
               }
@@ -540,6 +551,7 @@
          }
          if(pq->ccb == NULL || error)
               pdu_free(sp->isc, pq);
+         mtx_lock(&sp->io_mtx);
      }
      return ndone;
 }
@@ -558,13 +570,13 @@

      sp->flags |= ISC_SM_RUNNING;
      do {
+         mtx_lock(&sp->io_mtx);
          if(sp->flags & ISC_SM_HOLD)
               odone = 0;
          else
               odone = proc_out(sp);
          sdebug(7, "odone=%d", odone);
          if(odone == 0) {
-              mtx_lock(&sp->io_mtx);
 #ifdef ISC_OWAITING
               sp->flags |= ISC_OWAITING;
 #endif
@@ -574,8 +586,8 @@
 #ifdef ISC_OWAITING
               sp->flags &= ~ISC_OWAITING;
 #endif
-              mtx_unlock(&sp->io_mtx);
          }
+         mtx_unlock(&sp->io_mtx);
      } while(sp->flags & ISC_SM_RUN);

      sp->flags &= ~ISC_SM_RUNNING;
--
A: Yes.                                   Pierre Beyssac pb at enst.fr
>Q: Are you sure?
>>A: Because it reverses the logical flow of conversation.
>>>Q: Why is top posting annoying in email?
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