Date: Thu, 18 Mar 2004 10:23:37 -0800 (PST) From: Alan Cox <alc@FreeBSD.org> To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/dev/md md.c Message-ID: <200403181823.i2IINbDA065857@repoman.freebsd.org>
next in thread | raw e-mail | index | archive | help
alc 2004/03/18 10:23:37 PST
FreeBSD src repository
Modified files:
sys/dev/md md.c
Log:
Utilize sf_buf_alloc() and sf_buf_free() to implement the ephemeral
mappings required by mdstart_swap(). On i386, if the ephemeral mapping
is already in the sf_buf mapping cache, a swap-backed md performs
similarly to a malloc-backed md. Even if the ephemeral mapping is not
cached, this implementation is still faster. On 64-bit platforms, this
change has the effect of using the direct virtual-to-physical mapping,
avoiding ephemeral mapping overheads, such as TLB shootdowns on SMPs.
On a 2.4GHz, 400MHz FSB P4 Xeon configured with 64K sf_bufs and
"mdmfs -S -o async -s 128m md /mnt"
before:
dd if=/dev/md0 of=/dev/null bs=64k
134217728 bytes transferred in 0.430923 secs (311465697 bytes/sec)
after with cold sf_buf cache:
dd if=/dev/md0 of=/dev/null bs=64k
134217728 bytes transferred in 0.367948 secs (364773576 bytes/sec)
after with warm sf_buf cache:
dd if=/dev/md0 of=/dev/null bs=64k
134217728 bytes transferred in 0.252826 secs (530870010 bytes/sec)
malloc-backed md:
dd if=/dev/md0 of=/dev/null bs=64k
134217728 bytes transferred in 0.253126 secs (530240978 bytes/sec)
Revision Changes Path
1.117 +9 -9 src/sys/dev/md/md.c
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200403181823.i2IINbDA065857>