@@ -58,7 +58,7 @@ int qemu_v9fs_synth_add_file(V9fsSynthNode *parent, int mode,
/* for READDIR test */
#define QTEST_V9FS_SYNTH_READDIR_DIR "ReadDirDir"
#define QTEST_V9FS_SYNTH_READDIR_FILE "ReadDirFile%d"
-#define QTEST_V9FS_SYNTH_READDIR_NFILES 100
+#define QTEST_V9FS_SYNTH_READDIR_NFILES 2000
/* Any write to the "FLUSH" file is handled one byte at a time by the
* backend. If the byte is zero, the backend returns success (ie, 1),
@@ -15,6 +15,17 @@
#include "libqos/virtio-9p.h"
#include "libqos/qgraph.h"
+/*
+ * to benchmark the real time (not CPU time) that elapsed between start of
+ * a request and arrival of its response
+ */
+static double wall_time(void) {
+ struct timeval t;
+ struct timezone tz;
+ gettimeofday(&t, &tz);
+ return t.tv_sec + t.tv_usec * 0.000001;
+}
+
#define QVIRTIO_9P_TIMEOUT_US (10 * 1000 * 1000)
static QGuestAllocator *alloc;
@@ -36,7 +47,7 @@ static void pci_config(void *obj, void *data, QGuestAllocator *t_alloc)
g_free(tag);
}
-#define P9_MAX_SIZE 4096 /* Max size of a T-message or R-message */
+#define P9_MAX_SIZE (256*1024) /* Max size of a T-message or R-message */
typedef struct {
QTestState *qts;
@@ -593,12 +604,32 @@ static void fs_readdir(void *obj, void *data, QGuestAllocator *t_alloc)
v9fs_req_wait_for_reply(req, NULL);
v9fs_rlopen(req, &qid, NULL);
+ const double start = wall_time();
+
req = v9fs_treaddir(
v9p, 1/*fid*/, 0/*offset*/, P9_MAX_SIZE - P9_IOHDRSZ/*count*/,
0/*tag*/
);
+ const double treaddir = wall_time();
v9fs_req_wait_for_reply(req, NULL);
+ const double waitforreply = wall_time();
v9fs_rreaddir(req, &count, &nentries, &entries);
+ const double end = wall_time();
+
+ printf("\nTime client spent on sending T_readdir: %fs\n\n", treaddir - start);
+ printf("Time client spent for waiting for reply from server: %fs [MOST IMPORTANT]\n", waitforreply - start);
+ printf("(This is the most important value, because it reflects the time\n"
+ "the 9p server required to process and return the result of the\n"
+ "T_readdir request.)\n\n");
+
+ printf("Total client time: %fs\n", end - start);
+ printf("(NOTE: this time is not relevant; this huge time comes from\n"
+ "inefficient qtest_memread() calls. So you can discard this\n"
+ "value as a problem of this test client implementation while\n"
+ "processing the received server T_readdir reply.)\n\n");
+
+ printf("Details of response message data: R_readddir nentries=%d rbytes=%d\n",
+ nentries, count);
/*
* Assuming msize (P9_MAX_SIZE) is large enough so we can retrieve all
This patch is not intended to be merged. It just provides a temporary benchmark foundation for coneniently A/B comparison of the subsequent 9p READDIR optimization patches: * hw/9pfs/9p-synth: increase amount of simulated files for READDIR test to 2000 files. * tests/virtio-9p: measure wall time that elapsed between sending T_readdir request and arrival of R_readdir response and print out that measured duration, as well as amount of directory entries received, and the amount of bytes of the response message. * tests/virtio-9p: increased msize to 256kiB to allow retrieving all 2000 files (simulated by synth backend) with only one READDIR request. Running this benchmark is fairly quick & simple and does not require any guest OS installation or other prerequisites: cd build make && make tests/qos-test export QTEST_QEMU_BINARY=x86_64-softmmu/qemu-system-x86_64 tests/qos-test -p $(tests/qos-test -l | grep readdir/basic) Since this benchmark uses the 9p synth backend, the host machine's IO hardware (SSDs/HDDs) is not relevant for the benchmark result, because the synth backend's readdir implementation returns immediately (without any blocking IO that would happen with a real-life backend) and just returns already prepared, simulated directory entries directly from RAM. So this benchmark focuses on the efficiency of the 9p controller code (or top half) for READDIR request handling. Signed-off-by: Christian Schoenebeck <qemu_oss@crudebyte.com> --- hw/9pfs/9p-synth.h | 2 +- tests/virtio-9p-test.c | 33 ++++++++++++++++++++++++++++++++- 2 files changed, 33 insertions(+), 2 deletions(-)