From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ffbox0-bg.mplayerhq.hu (ffbox0-bg.ffmpeg.org [79.124.17.100]) by master.gitmailbox.com (Postfix) with ESMTP id 90C3E406CC for ; Fri, 28 Jan 2022 12:18:57 +0000 (UTC) Received: from [127.0.1.1] (localhost [127.0.0.1]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTP id 39E9B68B180; Fri, 28 Jan 2022 14:18:54 +0200 (EET) Received: from mail0.khirnov.net (red.khirnov.net [176.97.15.12]) by ffbox0-bg.mplayerhq.hu (Postfix) with ESMTPS id A063768AF6B for ; Fri, 28 Jan 2022 14:18:47 +0200 (EET) Received: from localhost (localhost [IPv6:::1]) by mail0.khirnov.net (Postfix) with ESMTP id BBA3D24017C for ; Fri, 28 Jan 2022 13:18:46 +0100 (CET) Received: from mail0.khirnov.net ([IPv6:::1]) by localhost (mail0.khirnov.net [IPv6:::1]) (amavisd-new, port 10024) with ESMTP id kETwRvhEGGZG for ; Fri, 28 Jan 2022 13:18:45 +0100 (CET) Received: from lain.red.khirnov.net (lain.red.khirnov.net [IPv6:2001:67c:1138:4306::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "lain.red.khirnov.net", Issuer "smtp.khirnov.net SMTP CA" (verified OK)) by mail0.khirnov.net (Postfix) with ESMTPS id 66E4E240179 for ; Fri, 28 Jan 2022 13:18:45 +0100 (CET) Received: by lain.red.khirnov.net (Postfix, from userid 1000) id 7D61816008E; Fri, 28 Jan 2022 13:18:45 +0100 (CET) From: Anton Khirnov To: FFmpeg development discussions and patches In-Reply-To: <20220125102109.522-1-michael@niedermayer.cc> References: <20220125102109.522-1-michael@niedermayer.cc> Mail-Followup-To: FFmpeg development discussions and patches Date: Fri, 28 Jan 2022 13:18:45 +0100 Message-ID: <164337232528.23111.7444999659506493047@lain.red.khirnov.net> User-Agent: alot/0.8.1 MIME-Version: 1.0 Subject: Re: [FFmpeg-devel] [PATCH 1/2] avutil/random_seed: Speed up fate test X-BeenThere: ffmpeg-devel@ffmpeg.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FFmpeg development discussions and patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: FFmpeg development discussions and patches Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ffmpeg-devel-bounces@ffmpeg.org Sender: "ffmpeg-devel" Archived-At: List-Archive: List-Post: Quoting Michael Niedermayer (2022-01-25 11:21:08) > This decreases the quality of the seeds during the test, it does not affect > the seeds outside the test. > There is a small chance that this causes test failures, if that happens > the threshold needs adjusting > > Testing on an idle x86_64 system shows that this passes even with the test strength > increased to 32768 from 256 with 0 retries > So test failures are not anticipated > Lowering the threshold from 3 to 2 causes failure at test strength of 32768 > > Signed-off-by: Michael Niedermayer > --- > libavutil/random_seed.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/libavutil/random_seed.c b/libavutil/random_seed.c > index 70dc509d2f..509b74936c 100644 > --- a/libavutil/random_seed.c > +++ b/libavutil/random_seed.c > @@ -95,7 +95,7 @@ static uint32_t get_generic_seed(void) > last_td = t - last_t; > buffer[++i & 511] += last_td % 3294638521U; > if ((t - init_t) >= CLOCKS_PER_SEC>>5) > - if (last_i && i - last_i > 4 || i - last_i > 64 || TEST && i - last_i > 8) > + if (last_i && i - last_i > 4 || i - last_i > 64 || TEST && i - last_i > 3) On my Ryzen 5950x, this brings the test runtime from > 60s to ~30s, which is a good improvement, but still quite a lot (the entire FATE run with -j32 and without the random-seed test is ~40s). How about something like this instead (takes about 8s on my machines, observed no test failures): diff --git a/libavutil/random_seed.c b/libavutil/random_seed.c index 70dc509d2f..b006a75c39 100644 --- a/libavutil/random_seed.c +++ b/libavutil/random_seed.c @@ -73,6 +73,7 @@ static uint32_t get_generic_seed(void) static uint32_t buffer[512] = { 0 }; unsigned char digest[20]; uint64_t last_i = i; + uint64_t cnt = 0; av_assert0(sizeof(tmp) >= av_sha_size); @@ -88,9 +89,11 @@ static uint32_t get_generic_seed(void) for (;;) { clock_t t = clock(); - if (last_t + 2*last_td + (CLOCKS_PER_SEC > 1000) >= t) { + if (last_t + 2*last_td + (CLOCKS_PER_SEC > 1000) >= t && + !(TEST && cnt > (1 << 15))) { last_td = t - last_t; buffer[i & 511] = 1664525*buffer[i & 511] + 1013904223 + (last_td % 3294638521U); + cnt++; } else { last_td = t - last_t; buffer[++i & 511] += last_td % 3294638521U; -- Anton Khirnov _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".