[0/2] SUNRPC consumer for the bulk page allocator

Message

Chuck Lever III March 23, 2021, 3:09 p.m. UTC

This patch set and the measurements below are based on yesterday's
bulk allocator series:

git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux.git mm-bulk-rebase-v5r9

The patches change SUNRPC to invoke the array-based bulk allocator
instead of alloc_page().

The micro-benchmark results are promising. I ran a mixture of 256KB
reads and writes over NFSv3. The server's kernel is built with KASAN
enabled, so the comparison is exaggerated but I believe it is still
valid.

I instrumented svc_recv() to measure the latency of each call to
svc_alloc_arg() and report it via a trace point. The following
results are averages across the trace events.

Single page: 25.007 us per call over 532,571 calls
Bulk list:    6.258 us per call over 517,034 calls
Bulk array:   4.590 us per call over 517,442 calls

For SUNRPC, the simplicity and better performance of the array-based
API makes it superior to the list-based API.

---

Chuck Lever (2):
      SUNRPC: Set rq_page_end differently
      SUNRPC: Refresh rq_pages using a bulk page allocator


 net/sunrpc/svc_xprt.c | 33 +++++++++++++++++----------------
 1 file changed, 17 insertions(+), 16 deletions(-)

--
Chuck Lever