From: Steve Sistare Date: Fri, 19 Sep 2025 13:58:30 +0000 (-0700) Subject: tests/qtest: optimize qtest_get_machines X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e16d7a732124ccaf9960920a9b64f4cf95f8fdab;p=thirdparty%2Fqemu.git tests/qtest: optimize qtest_get_machines qtest_get_machines returns the machines supported by the QEMU binary described by an environment variable and caches the result. If the next call to qtest_get_machines passes the same variable name, the cached result is returned, but if the name changes, the caching is defeated. To make caching more effective, remember the path of the QEMU binary instead. Different env vars, eg QTEST_QEMU_BINARY_SRC and QTEST_QEMU_BINARY_DST, usually resolve to the same path. Before the optimization, the test /x86_64/migration/precopy/unix/plain exec's QEMU and calls query-machines 3 times. After optimization, that only happens once. This does not significantly speed up the tests, but it reduces QTEST_LOG output, and launches fewer QEMU instances, making it easier to debug problems. Signed-off-by: Steve Sistare Reviewed-by: Fabiano Rosas Message-ID: <87h5ymdzrf.fsf@pond.sub.org> Link: https://lore.kernel.org/qemu-devel/1758290310-349623-1-git-send-email-steven.sistare@oracle.com Signed-off-by: Fabiano Rosas --- diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c index 94526b7f9cc..f3d4e0829a3 100644 --- a/tests/qtest/libqtest.c +++ b/tests/qtest/libqtest.c @@ -1630,7 +1630,8 @@ static void qtest_free_machine_list(struct MachInfo *machines) static struct MachInfo *qtest_get_machines(const char *var) { static struct MachInfo *machines; - static char *qemu_var; + static char *qemu_bin; + const char *new_qemu_bin; QDict *response, *minfo; QList *list; const QListEntry *p; @@ -1639,9 +1640,10 @@ static struct MachInfo *qtest_get_machines(const char *var) QTestState *qts; int idx; - if (g_strcmp0(qemu_var, var)) { - g_free(qemu_var); - qemu_var = g_strdup(var); + new_qemu_bin = qtest_qemu_binary(var); + if (g_strcmp0(qemu_bin, new_qemu_bin)) { + g_free(qemu_bin); + qemu_bin = g_strdup(new_qemu_bin); /* new qemu, clear the cache */ qtest_free_machine_list(machines); @@ -1654,7 +1656,7 @@ static struct MachInfo *qtest_get_machines(const char *var) silence_spawn_log = !g_test_verbose(); - qts = qtest_init_ext(qemu_var, "-machine none", NULL, true); + qts = qtest_init_ext(var, "-machine none", NULL, true); response = qtest_qmp(qts, "{ 'execute': 'query-machines' }"); g_assert(response); list = qdict_get_qlist(response, "return");