Date: Tue, 19 Sep 1995 20:35:03 +1000 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, rgrimes@gndrsh.aac.dev.com Cc: current@freebsd.org, rkw@dataplex.net, wollman@lcs.mit.edu Subject: Re: Which SUP files are available and where ? Message-ID: <199509191035.UAA04813@godzilla.zeta.org.au>
next in thread | raw e-mail | index | archive | help
>> I thought that the CPU ran out of power before the pipe was half full, >> even doing raw data movement for nfs. >I have done iozones over NFS on 100BaseTx networking and seen numbers >well in excess of 3MBytes/s reading (forget about writting, we all >know sync nfs is dog slow at that). 3MB/s is less than half full. >> For sup it will have to traverse >> file systems so it will be hard to get more than 1MB of throughput per >> file system. >File system bandwidth is not a problem. Again, I can produce iozone >results in excess of 6MB/sec quite easily on local fast disks. iozone is not representative of anything except huge sequential accesses to huge sequential files. On a disk that has an iozone speed of 4-5MB/s here, the throughput of `cvs -Q co bin' is 30K/sec (2562K, 85.05 real, 12.69 user, 20.96 sys) (the cvs repository is on a separate disk). The throughput of `cp -pR bin bin~' is 79K/sec (2562K, 33.41 real, 0.10 user, 3.04 sys). The throughput of `cp -pR bin separate_slower_disk/bin' is 56K (2562K, 46.50 real, 0.10 user, 3.50 sys). Abysmal results like this are typical for accessing small files. >> Is it as fast as cvs co ;-). >A _LOT_ faster when you are talking about the two running over local >ethernet. NFS gets in the way a bit. Sup is slow over long RTT links >due to the 2 RTT needed for many of the things it does, it is blazing >fast on local networks (and smokes on 100Mb/s networks :-)). Cancel the previous `;-)'. sup should be faster than cvs co but it can hardly be faster than cp -pR, and cp -pR is _slow_. Bruce
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199509191035.UAA04813>