Date:   Fri, 17 Feb 2023 18:10:10 -0500
From:   Peter Xu <peterx@redhat.com>
To:     Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc:     David Hildenbrand <david@redhat.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, Axel Rasmussen <axelrasmussen@google.com>,
        Mike Rapoport <rppt@linux.vnet.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Nadav Amit <nadav.amit@gmail.com>
Subject: Re: [PATCH] mm/uffd: UFFD_FEATURE_WP_ZEROPAGE
Message-ID: <Y/AJUi4o5hOKDkgy@x1n>
References: <20230215210257.224243-1-peterx@redhat.com>
 <7eb2bce9-d0b1-a0e3-8be3-f28d858a61a0@redhat.com>
 <Y+5Z+88Z3T2TyxUI@x1n>
 <4f64d62f-c21d-b7c8-640e-d41742bbbe7b@redhat.com>
 <Y+5uIS5E9sTLi41T@x1n>
 <456f8e2e-9554-73a3-4fdb-be21f9cc54b6@redhat.com>
 <Y+6NKPuty9V3nycI@x1n>
 <427298c4-0da9-059f-02ff-c5147d317c87@collabora.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <427298c4-0da9-059f-02ff-c5147d317c87@collabora.com>
Precedence: bulk

Hi, Muhammad,

On Fri, Feb 17, 2023 at 05:31:19PM +0500, Muhammad Usama Anjum wrote:
> I've just ran my single threaded selftest [1] over an over again to get
> some numbers.
> 
> Without zeropage
> qemu has 6 cores: 26.0355

Did you count in the time of read prefault?  Or did you not prefault at
all?

> With zeropage
> qemu has 6 cores: 39.203
> 
> 33% worse performance with zero pages
> 
> Definitely, there can be better benchmark application. Please let me know
> if I should write better benchmarks on my end.
> 
> [1]
> https://lore.kernel.org/all/20230202112915.867409-7-usama.anjum@collabora.com

I'll have a closer look too next week.

Thanks,

-- 
Peter Xu