Re: [Virtio-fs] [PATCH 1/1] virtiofsd: Do not use a thread pool by default

[Dr. David Alan Gilbert]

* 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 <vgoyal@redhat.com>

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.



Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  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 <sys/file.h>
>  
> -#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