open_issues/performance/io_system/binutils_ld_64ksec: Move Xen lseek stuff...

open_issues/xen_lseek: ... here.

3 files changed, 3 insertions, 56 deletions

diff --git a/open_issues/performance/io_system/binutils_ld_64ksec.mdwn b/open_issues/performance/io_system/binutils_ld_64ksec.mdwn
index d0b8ea7f..931fd0ee 100644
--- a/open_issues/performance/io_system/binutils_ld_64ksec.mdwn
+++ b/open_issues/performance/io_system/binutils_ld_64ksec.mdwn
@@ -27,10 +27,6 @@ extracted from cdf7c161ebd4a934c9e705d33f5247fd52975612 sources, 2010-10-24.
 On the idle grubber, this one repeatedly takes a few minutes wall time to
 complete successfully, contrary to a few seconds on a GNU/Linux system.
 
-> On order of slowness may in fact be due to a Xen-specific issue, see
-> [[xen_lseek]].  (But there are probably still one or two orders left, even
-> without Xen.)
-
 While processing the object files, there is heavy interaction with the relevant
 [[hurd/translator/ext2fs]] process.  Running [[hurd/debugging/rpctrace]] on
 the testee shows that (primarily) an ever-repeating series of `io_seek` and
@@ -38,19 +34,6 @@ the testee shows that (primarily) an ever-repeating series of `io_seek` and
 shows the equivalent thing (`_llseek`, `read`) -- but Linux' I/O system isn't
 as slow as the Hurd's.
 
----
-
-IRC, freenode, #hurd, 2011-09-01:
-
-    <youpi> hum, f951 does myriads of   71->io_seek_request (32768 0) = 0 32768
-    <youpi> no wonder it's slow
-    <youpi> unfortunately that's also what it does on linux, the system call is
-      just less costly
-    <youpi> apparently gfortran calls io_seek for, like, every token of the
-      sourced file
-    <youpi> (fgetpos actually, but that's the same)
-    <youpi> and it is indeed about 10 times slower under Xen for some reason
-
-Also see testcase [[test-lseek.c]] and [[test-mach.c]]
-
-[[!tag open_issue_xen]]
+As Samuel figured out later, this slowness may in fact be due to a Xen-specific
+issue, see [[Xen_lseek]].  After the latter has been addressed, we can
+re-evaluate this issue here.
diff --git a/open_issues/performance/io_system/test-lseek.c b/open_issues/performance/io_system/test-lseek.c
deleted file mode 100644
index 667dce66..00000000
--- a/open_issues/performance/io_system/test-lseek.c
+++ /dev/null
@@ -1,17 +0,0 @@
-#include <stdio.h>
-#include <math.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <sys/time.h>
-#define N 100000
-int main(void) {
-	int fd = open("test.c", O_RDONLY);
-	struct timeval tv1, tv2;
-	int i;
-	gettimeofday(&tv1, NULL);
-	for (i = 0; i < N; i++)
-		lseek(fd, 0, SEEK_CUR);
-	gettimeofday(&tv2, NULL);
-	printf("%fµs\n", (float)((tv2.tv_sec-tv1.tv_sec) * 1000000 + tv2.tv_usec - tv1.tv_usec)/N);
-	return 0;
-}
diff --git a/open_issues/performance/io_system/test-mach.c b/open_issues/performance/io_system/test-mach.c
deleted file mode 100644
index 90337346..00000000
--- a/open_issues/performance/io_system/test-mach.c
+++ /dev/null
@@ -1,19 +0,0 @@
-#define _GNU_SOURCE
-#include <stdio.h>
-#include <fcntl.h>
-#include <mach/mach.h>
-#define N 1000000
-int main(void) {
-	struct timeval tv1, tv2;
-	int i;
-	task_t task;
-	task = mach_task_self();
-	mach_port_urefs_t refs;
-	gettimeofday(&tv1, NULL);
-	for (i = 0; i < N; i++) {
-		mach_port_get_refs(task, task, MACH_PORT_RIGHT_RECEIVE, &refs);
-	}
-	gettimeofday(&tv2, NULL);
-	printf("%fµs\n", (float)((tv2.tv_sec-tv1.tv_sec) * 1000000 + tv2.tv_usec - tv1.tv_usec)/N);
-	return 0;
-}