From: Mikulas Patocka <mpatocka@redhat.com>
To: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Cc: Mike Snitzer <msnitzer@redhat.com>,
Herbert Xu <herbert@gondor.apana.org.au>,
"David S. Miller" <davem@davemloft.net>,
Milan Broz <mbroz@redhat.com>,
djeffery@redhat.com, dm-devel@redhat.com, qat-linux@intel.com,
linux-crypto@vger.kernel.org, guazhang@redhat.com,
jpittman@redhat.com, ahsan.atta@intel.com
Subject: Re: [PATCH 1/4] qat: fix misunderstood -EBUSY return code
Date: Wed, 3 Jun 2020 15:54:09 -0400 (EDT) [thread overview]
Message-ID: <alpine.LRH.2.02.2006031553170.9890@file01.intranet.prod.int.rdu2.redhat.com> (raw)
In-Reply-To: <20200603165526.GA94360@silpixa00400314>
On Wed, 3 Jun 2020, Giovanni Cabiddu wrote:
> > > > +bool adf_should_back_off(struct adf_etr_ring_data *ring)
> > > > +{
> > > > + return atomic_read(ring->inflights) > ADF_MAX_INFLIGHTS(ring->ring_size, ring->msg_size) * 15 / 16;
> > > How did you came up with 15/16?
> >
> > I want the sender to back off before the queue is full, to avoid
> > busy-waiting. There may be more concurrent senders, so we want to back off
> > at some point before the queue is full.
> Yes, I understood this. My question was about the actual number.
> 93% of the depth of the queue.
I just guessed the value. If you have some benchmark, you can try
different values, to test if they perform better.
Mikulas
prev parent reply other threads:[~2020-06-03 19:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-01 16:03 [PATCH 1/4] qat: fix misunderstood -EBUSY return code Mikulas Patocka
2020-06-02 22:05 ` Giovanni Cabiddu
2020-06-03 8:31 ` Mikulas Patocka
2020-06-03 12:25 ` Herbert Xu
2020-06-03 16:55 ` Giovanni Cabiddu
2020-06-03 19:54 ` Mikulas Patocka [this message]
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