On Mon, 24 Apr 2000, Artur Skawina wrote:
> kumon@flab.fujitsu.co.jp wrote:
> >
> > In the heavy duty case, csum_partial_copy_generic() becomes the new
> > winner of the worst time consuming function with the poll()
> > optimization. We are arranging the global figure now.
> >
> > Though csum_partial_copy_generic() is highly optimized with
> > hand-crafted code, it eats lots of time. It may be inevitable, but may
> > be reducible. We are now investigating why it does.
>
> csum_partial_copy_generic() could certainly be more optimized;
> attached is a snapshot of a version that does upto 20% better in
> dumb benchmarks, if and what difference there is for real loads
> i haven't yet measured.
>
> [patch vs 2.3.99pre6pre5, offsets are wrong]
>
here is a patch against apache-1.3 which forces it to align the length of
its headers to a 32-byte boundary. if your benchmark is requesting
objects greater than ~4k in size this will cause apache to generate
writev()s such as:
writev(3, [{"HTTP/1.1 200 OK\r\nDate: Tue, 25 A"..., 288}, {"<!DOCTYPE
HTML PUBLIC \"-//W3C//D"..., 32768}], 2) = 33056
which are 32-byte aligned, and sized...
folks have observed a performance boost with other web-servers with this
technique. i haven't tested it at all, just thought you might want to try
it if you're trying out new csum_partial_copy_generic()s.
-dean
Index: src/main/buff.c
===================================================================
RCS file: /home/cvs/apache-1.3/src/main/buff.c,v
retrieving revision 1.96
diff -u -r1.96 buff.c
--- src/main/buff.c 2000/03/04 20:51:02 1.96
+++ src/main/buff.c 2000/04/25 01:59:00
@@ -390,8 +390,11 @@
/* overallocate so that we can put a chunk trailer of CRLF into this
* buffer */
- if (flags & B_WR)
- fb->outbase = ap_palloc(p, fb->bufsiz + 2);
+ if (flags & B_WR) {
+#define ALIGN (32)
+ fb->outbase = ap_palloc(p, fb->bufsiz + 2 + ALIGN);
+ fb->outbase += ALIGN - ((long)fb->outbase % ALIGN);
+ }
else
fb->outbase = NULL;
Index: src/main/http_protocol.c
===================================================================
RCS file: /home/cvs/apache-1.3/src/main/http_protocol.c,v
retrieving revision 1.289
diff -u -r1.289 http_protocol.c
--- src/main/http_protocol.c 2000/02/20 01:14:47 1.289
+++ src/main/http_protocol.c 2000/04/25 01:59:00
@@ -1445,6 +1445,21 @@
if (bs >= 255 && bs <= 257)
ap_bputs("X-Pad: avoid browser bug" CRLF, client);
+#define ALIGN (32)
+ ap_bgetopt(client, BO_BYTECT, &bs);
+ bs += 2; /* for the final terminating empty line */
+ if (bs % ALIGN) {
+ ap_bputc('X', client);
+ ap_bputc(':', client);
+ bs += 4; /* 2 for "X:" and 2 for the final CRLF */
+ while (bs % ALIGN) {
+ ap_bputc('X', client);
+ ++bs;
+ }
+ ap_bputc('\r', client);
+ ap_bputc('\n', client);
+ }
+
ap_bputs(CRLF, client); /* Send the terminating empty line */
}
-
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This archive was generated by hypermail 2b29 : Sun Apr 30 2000 - 21:00:08 EST