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HAS_REPLYTO(0.30)[pvorel@suse.cz]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MISSING_XM_UA(0.00)[]; TO_DN_SOME(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; FUZZY_RATELIMITED(0.00)[rspamd.com]; RCVD_TLS_ALL(0.00)[]; RCPT_COUNT_THREE(0.00)[4]; FROM_HAS_DN(0.00)[]; DKIM_SIGNED(0.00)[suse.cz:s=susede2_rsa,suse.cz:s=susede2_ed25519]; FROM_EQ_ENVFROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; REPLYTO_EQ_FROM(0.00)[] X-Virus-Scanned: clamav-milter 1.0.9 at in-5.smtp.seeweb.it X-Virus-Status: Clean Subject: Re: [LTP] [PATCH 1/1] readahead02: Sleep 1.5 msec to fix problem on bare metal X-BeenThere: ltp@lists.linux.it X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux Test Project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Petr Vorel Cc: ltp@lists.linux.it Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ltp-bounces+ltp=archiver.kernel.org@lists.linux.it Sender: "ltp" > Hi! > > This fixes ppc64le bare metal. It looks like kernel needs some time to > > update counters. > In this case I think that something is needed for the kernel to actually > do some readahead. The readahead() syscall is supposed to initiate > readahead but kernel will need some time for the actual readahead to > happen. And how much time will depend on the I/O speed and saturation of > the I/O bus/disk. > Adding a short sleep is a good start. However I'm afraid that we will > need a bit more complex solution to this problem. Maybe do a short > sleep, check the cache size and if it increased more than some > threshold, sleep again. > Something as: > int retries = MAX_RETRIES; > unsigned long cached_prev, cached_cur = get_cached_size(); > do { > usleep(SHORT_SLEEP); > cached_prev = cached_cur; > cached_cur = get_cached_size(); > if (cached_cur < cached_prev) > break; > if (cached_cur-cached_prev < CACHE_INC_THRESHOLD) > break; > } while (retries-- > 0); Yeah, few loops with shorter usleep() and proactive checking is for sure way better than single usleep(). Will you please have time to send the above as a patch? I'll test it for you. Kind regards, Petr -- Mailing list info: https://lists.linux.it/listinfo/ltp