diff options
| -rw-r--r-- | aio-posix.c | 58 | ||||
| -rw-r--r-- | aio-win32.c | 3 | ||||
| -rw-r--r-- | async.c | 3 | ||||
| -rw-r--r-- | include/block/aio.h | 10 | ||||
| -rw-r--r-- | iothread.c | 4 | ||||
| -rw-r--r-- | trace-events | 2 |
6 files changed, 71 insertions, 9 deletions
diff --git a/aio-posix.c b/aio-posix.c index 5216d82290..15855715d4 100644 --- a/aio-posix.c +++ b/aio-posix.c @@ -550,7 +550,7 @@ static bool try_poll_mode(AioContext *ctx, bool blocking) if (blocking && ctx->poll_max_ns && ctx->poll_disable_cnt == 0) { /* See qemu_soonest_timeout() uint64_t hack */ int64_t max_ns = MIN((uint64_t)aio_compute_timeout(ctx), - (uint64_t)ctx->poll_max_ns); + (uint64_t)ctx->poll_ns); if (max_ns) { poll_set_started(ctx, true); @@ -576,6 +576,7 @@ bool aio_poll(AioContext *ctx, bool blocking) int ret = 0; bool progress; int64_t timeout; + int64_t start = 0; aio_context_acquire(ctx); progress = false; @@ -593,6 +594,10 @@ bool aio_poll(AioContext *ctx, bool blocking) ctx->walking_handlers++; + if (ctx->poll_max_ns) { + start = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); + } + if (try_poll_mode(ctx, blocking)) { progress = true; } else { @@ -635,6 +640,47 @@ bool aio_poll(AioContext *ctx, bool blocking) atomic_sub(&ctx->notify_me, 2); } + /* Adjust polling time */ + if (ctx->poll_max_ns) { + int64_t block_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - start; + + if (block_ns <= ctx->poll_ns) { + /* This is the sweet spot, no adjustment needed */ + } else if (block_ns > ctx->poll_max_ns) { + /* We'd have to poll for too long, poll less */ + int64_t old = ctx->poll_ns; + + if (ctx->poll_shrink) { + ctx->poll_ns /= ctx->poll_shrink; + } else { + ctx->poll_ns = 0; + } + + trace_poll_shrink(ctx, old, ctx->poll_ns); + } else if (ctx->poll_ns < ctx->poll_max_ns && + block_ns < ctx->poll_max_ns) { + /* There is room to grow, poll longer */ + int64_t old = ctx->poll_ns; + int64_t grow = ctx->poll_grow; + + if (grow == 0) { + grow = 2; + } + + if (ctx->poll_ns) { + ctx->poll_ns *= grow; + } else { + ctx->poll_ns = 4000; /* start polling at 4 microseconds */ + } + + if (ctx->poll_ns > ctx->poll_max_ns) { + ctx->poll_ns = ctx->poll_max_ns; + } + + trace_poll_grow(ctx, old, ctx->poll_ns); + } + } + aio_notify_accept(ctx); /* if we have any readable fds, dispatch event */ @@ -678,12 +724,16 @@ void aio_context_setup(AioContext *ctx) #endif } -void aio_context_set_poll_params(AioContext *ctx, int64_t max_ns, Error **errp) +void aio_context_set_poll_params(AioContext *ctx, int64_t max_ns, + int64_t grow, int64_t shrink, Error **errp) { - /* No thread synchronization here, it doesn't matter if an incorrect poll - * timeout is used once. + /* No thread synchronization here, it doesn't matter if an incorrect value + * is used once. */ ctx->poll_max_ns = max_ns; + ctx->poll_ns = 0; + ctx->poll_grow = grow; + ctx->poll_shrink = shrink; aio_notify(ctx); } diff --git a/aio-win32.c b/aio-win32.c index d0e40a854c..d19dc429d8 100644 --- a/aio-win32.c +++ b/aio-win32.c @@ -395,7 +395,8 @@ void aio_context_setup(AioContext *ctx) { } -void aio_context_set_poll_params(AioContext *ctx, int64_t max_ns, Error **errp) +void aio_context_set_poll_params(AioContext *ctx, int64_t max_ns, + int64_t grow, int64_t shrink, Error **errp) { error_setg(errp, "AioContext polling is not implemented on Windows"); } @@ -385,7 +385,10 @@ AioContext *aio_context_new(Error **errp) qemu_rec_mutex_init(&ctx->lock); timerlistgroup_init(&ctx->tlg, aio_timerlist_notify, ctx); + ctx->poll_ns = 0; ctx->poll_max_ns = 0; + ctx->poll_grow = 0; + ctx->poll_shrink = 0; return ctx; fail: diff --git a/include/block/aio.h b/include/block/aio.h index 3817d179fd..4dca54d9c7 100644 --- a/include/block/aio.h +++ b/include/block/aio.h @@ -134,8 +134,11 @@ struct AioContext { /* Number of AioHandlers without .io_poll() */ int poll_disable_cnt; - /* Maximum polling time in nanoseconds */ - int64_t poll_max_ns; + /* Polling mode parameters */ + int64_t poll_ns; /* current polling time in nanoseconds */ + int64_t poll_max_ns; /* maximum polling time in nanoseconds */ + int64_t poll_grow; /* polling time growth factor */ + int64_t poll_shrink; /* polling time shrink factor */ /* Are we in polling mode or monitoring file descriptors? */ bool poll_started; @@ -511,10 +514,13 @@ void aio_context_setup(AioContext *ctx); * aio_context_set_poll_params: * @ctx: the aio context * @max_ns: how long to busy poll for, in nanoseconds + * @grow: polling time growth factor + * @shrink: polling time shrink factor * * Poll mode can be disabled by setting poll_max_ns to 0. */ void aio_context_set_poll_params(AioContext *ctx, int64_t max_ns, + int64_t grow, int64_t shrink, Error **errp); #endif diff --git a/iothread.c b/iothread.c index 8dfd10dee6..28598b5463 100644 --- a/iothread.c +++ b/iothread.c @@ -98,7 +98,7 @@ static void iothread_complete(UserCreatable *obj, Error **errp) return; } - aio_context_set_poll_params(iothread->ctx, iothread->poll_max_ns, + aio_context_set_poll_params(iothread->ctx, iothread->poll_max_ns, 0, 0, &local_error); if (local_error) { error_propagate(errp, local_error); @@ -158,7 +158,7 @@ static void iothread_set_poll_max_ns(Object *obj, Visitor *v, iothread->poll_max_ns = value; if (iothread->ctx) { - aio_context_set_poll_params(iothread->ctx, value, &local_err); + aio_context_set_poll_params(iothread->ctx, value, 0, 0, &local_err); } out: diff --git a/trace-events b/trace-events index 7fe3a1b0e8..1181486454 100644 --- a/trace-events +++ b/trace-events @@ -28,6 +28,8 @@ # aio-posix.c run_poll_handlers_begin(void *ctx, int64_t max_ns) "ctx %p max_ns %"PRId64 run_poll_handlers_end(void *ctx, bool progress) "ctx %p progress %d" +poll_shrink(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64 +poll_grow(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64 # thread-pool.c thread_pool_submit(void *pool, void *req, void *opaque) "pool %p req %p opaque %p" |