From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 16 Feb 2021 13:04:29 -0500 From: Vivek Goyal Message-ID: <20210216180429.GC3196@redhat.com> References: <20210210182744.27324-1-vgoyal@redhat.com> <20210210182744.27324-2-vgoyal@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Virtio-fs] [PATCH 1/1] virtiofsd: Do not use a thread pool by default List-Id: Development discussions about virtio-fs List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Dr. David Alan Gilbert" Cc: virtio-fs@redhat.com, qemu-devel@nongnu.org On Tue, Feb 16, 2021 at 05:55:26PM +0000, Dr. David Alan Gilbert wrote: > * Vivek Goyal (vgoyal@redhat.com) wrote: > > Currently we created a thread pool (With 64 max threads per pool) for > > each virtqueue. We hoped that this will provide us with better scalability > > and performance. > > > > But in practice, we are getting better numbers in most of the cases > > when we don't create a thread pool at all and a single thread per > > virtqueue receives the request and processes it. > > > > Hence, I am proposing that we switch to no thread pool by default > > (equivalent of --thread-pool-size=0). This will provide out of > > box better performance to most of the users. In fact other users > > have confirmed that not using a thread pool gives them better > > numbers. So why not use this as default. It can be changed when > > somebody can fix the issues with thread pool performance. > > > > Signed-off-by: Vivek Goyal > > OK, lets try it - I still worry it really means we're missing something > silly about them, you'd really think eventually the threads should help. Agreed. Once we figure out what are we missing with threading and start getting better performance with multi-threading, we will need to make thread pool default again. Vivek > > > > Reviewed-by: Dr. David Alan Gilbert > > > --- > > tools/virtiofsd/fuse_lowlevel.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/tools/virtiofsd/fuse_lowlevel.c b/tools/virtiofsd/fuse_lowlevel.c > > index e94b71110b..fbdf62ee9b 100644 > > --- a/tools/virtiofsd/fuse_lowlevel.c > > +++ b/tools/virtiofsd/fuse_lowlevel.c > > @@ -18,7 +18,7 @@ > > > > #include > > > > -#define THREAD_POOL_SIZE 64 > > +#define THREAD_POOL_SIZE 0 > > > > #define OFFSET_MAX 0x7fffffffffffffffLL > > > > -- > > 2.25.4 > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > > _______________________________________________ > Virtio-fs mailing list > Virtio-fs@listman.redhat.com > https://listman.redhat.com/mailman/listinfo/virtio-fs