Re: [PATCH 0/5] Add vhost-blk support

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Il 17/07/2012 10:29, Asias He ha scritto:
> So, vhost-blk at least saves ~6 syscalls for us in each request. 

Are they really 6?  If I/O is coalesced by a factor of 3, for example
(i.e. each exit processes 3 requests), it's really 2 syscalls per request.

Also, is there anything we can improve?  Perhaps we can modify epoll and
ask it to clear the eventfd for us (would save 2 reads)?  Or
io_getevents (would save 1)?

> I guess you mean qemu here. Yes, in theory, qemu's block layer can be
> improved to achieve similar performance as vhost-blk or kvm tool's
> userspace virito-blk has. But I think it makes no sense to prevent one
> solution becase there is another in theory solution called: we can do
> similar in qemu.

It depends.  Like vhost-scsi, vhost-blk has the problem of a crippled
feature set: no support for block device formats, non-raw protocols,
etc.  This makes it different from vhost-net.

So it begs the question, is it going to be used in production, or just a
useful reference tool?

Paolo
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [Samba]     [Device Mapper]     [CEPH Development]
  Powered by Linux